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1
Jarvis, C. "Spatial analysis of cluster randomised trials." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2018. http://researchonline.lshtm.ac.uk/4648971/.
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Cluster randomised trials (CRTs) often use geographical areas as the unit of randomisation. Despite this, explicit consideration of the location and spatial distribution of observations is rare. In many trials, the location of participants will have little importance, however in some, especially against infectious diseases, spillover effects due to participants being located close together may affect trial results. This PhD takes a multidisciplinary approach to apply and evaluate spatial analysis methods in CRTs, furthering understanding of how spatial analysis can complement traditional evaluation of CRTs. I began by conducting a systematic review of CRTs that used spatial analysis techniques. I found only 10 published papers, most of which being supplementary analyses of the main trial. I then conducted a spatial analysis of an Oral Polio Vaccine (OPV) transmission household CRT. This provided additional insights into the underlying mechanism of polio transmission that support the global cessation of OPV and emphasises the difficulties of the global eradication of polio. Following this, I performed a spatial reanalysis of an insecticide-treated bed net CRT, applying approaches from the systematic review and a new method I developed called cluster reallocation to assess the presence and impact of spatial spillover in the trial. This analysis confirmed the previous estimate of intervention effect while showing evidence of a spillover effect. I carried out simulation studies to evaluate the impact of spillover and spatial effects on the standard CRT model and compared spatial regression to non-spatial models. These simulations focus on how to generate spatial spillover effects and the magnitude needed before spatial consideration becomes important to CRTs. I found that non-spatial CRT models are relatively robust to spatial effects and that the use of spatial models does not appear to improve upon the non-spatial model. The collective findings of this thesis highlight that standard CRT approaches are typically robust to small scale spillover effects and consideration of the spatial distribution of observations appears to provide little utility in the main analysis of a trial. Despite this, spatial methods can provide additional insights into the mechanism of interventions and are well suited to secondary analyses of CRTs, especially with the increasing collection of GPS data in CRTs.
2
Hossain, A. "Missing data in cluster randomised trials." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2017. http://researchonline.lshtm.ac.uk/4646133/.
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Missing outcomes are a commonly occurring problem in cluster randomised trials, which can lead to biased and inefficient inference if ignored or handled inappropriately. Handling missing data in CRTs is complicated due to the hierarchical structure of the data. Two approaches for analysing such trials are cluster-level analysis and individual level analysis. An assumption regarding missing outcomes in CRTs that is sometimes plausible is that missingness depends on baseline covariates, but conditioning on these baseline covariates, not on the outcome itself, which is known as a covariate dependent missingness (CDM) mechanism. The aim of my thesis was to investigate the validity of the approaches to the analysis of CRTs for the three most common outcome types: continuous, binary and time-to-event, when outcomes are missing under the assumption of CDM. Missing outcomes were handled using complete records analysis (CRA) and multilevel multiple imputation (MMI). We investigated analytically, and through simulations, the validity of the different combinations of the analysis model and missing data handling approach for each of the three outcome types. Simulations studies were performed considering scenarios depending on whether the missingness mechanism is the same between the intervention groups and whether the covariate effect is the same between the intervention groups in the outcome model. Based on our analytical and simulations results, we give recommendations for which methods to use when the CDM assumption is thought to be plausible for missing outcomes. The key findings of this thesis are as follows. Continuous outcomes: Cluster-level analyses using CRA are in general biased unless the intervention groups have the same missingness mechanism and the same covariate effects on outcome in the data generating model. In the case of individual-level analysis, the linear mixed model (LMM) using CRA adjusted for covariates such that the CDM assumption holds gives unbiased estimates of intervention effect regardless of whether the missingness mechanism is the same or different between the intervention groups, and whether there is an interaction between intervention and baseline covariates in the data generating model for outcome, provided that such interaction is included in the model when required. There is no gain in terms of bias or efficiency of the estimates using MMI over CRA as long as both approaches use the same functional form of the same set of baseline covariates. Binary outcomes: The adjusted cluster-level estimator for estimating risk ratio (RR) using full data is consistent if the true data generating model is a log link model, the functional form of the baseline covariates is the same between the intervention groups, and the random effects distribution is the same between the intervention groups. Cluster-level analyses using CRA for estimating risk difference (RD) are in general biased. For estimating RR, cluster-level analyses using CRA are valid if the true data generating model has log link and the intervention groups have the same missingness mechanism and the same functional form of the covariates in the outcome model. In contrast, MMI followed by cluster-level analyses gives valid inferences for estimating RD and RR regardless of whether the missingness mechanism is the same or different between the intervention groups, and whether there is an interaction between intervention and baseline covariate in the outcome model, provided that such interaction is included in the imputation model when required. In the case of individual-level analysis, both random effects logistic regression (RELR) and generalised estimating equations (GEE) give valid inferences using both CRA (adjusted for covariates such that the CDM assumption holds) and MMI regardless of whether the missingness mechanism is the same or different between the intervention groups, and whether there is an interaction between intervention and baseline covariate in the outcome model, provided that such interaction is included in both the imputation model and the analysis model when required. Like continuous outcomes, in the absence of auxiliary variables, there is no benefit in performing MMI rather than doing CRA in terms of bias or efficiency of the estimates. Time-to-Event outcomes: In the case of censored data, the unadjusted cluster-level analysis for estimating rate ratio (RaR) is consistent when the event rates are small and the covariate effects are the same between the intervention groups. In contrast, the adjusted cluster-level analysis for estimating RaR is consistent for any event rates when the the covariate effects are the same between the intervention groups. The gamma shared frailty model as an individual-level analysis underestimates the standard errors (SEs) of the estimates when each intervention group has small number of clusters. The Williams approach performs better than the Greenwood approach for estimating the SEs of Kaplan-Meier (KM) estimates unless the event rate is low and the value of intraclass correlation coefficient is very small.Missing outcomes are a commonly occurring problem in cluster randomised trials, which can lead to biased and inefficient inference if ignored or handled inappropriately. Handling missing data in CRTs is complicated due to the hierarchical structure of the data. Two approaches for analysing such trials are cluster-level analysis and individual-level analysis. An assumption regarding missing outcomes in CRTs that is sometimes plausible is that missingness depends on baseline covariates, but conditioning on these baseline covariates, not on the outcome itself, which is known as a covariate dependent missingness (CDM) mechanism. The aim of my thesis was to investigate the validity of the approaches to the analysis of CRTs for the three most common outcome types: continuous, binary and time-to-event, when outcomes are missing under the assumption of CDM. Missing outcomes were handled using complete records analysis (CRA) and multilevel multiple imputation (MMI). We investigated analytically, and through simulations, the validity of the different combinations of the analysis model and missing data handling approach for each of the three outcome types. Simulations studies were performed considering scenarios depending on whether the missingness mechanism is the same between the intervention groups and whether the covariate effect is the same between the intervention groups in the outcome model. Based on our analytical and simulations results, we give recommendations for which methods to use when the CDM assumption is thought to be plausible for missing outcomes. The key findings of this thesis are as follows. Continuous outcomes: Cluster-level analyses using CRA are in general biased unless the intervention groups have the same missingness mechanism and the same covariate effects on outcome in the data generating model. In the case of individual-level analysis, the linear mixed model (LMM) using CRA adjusted for covariates such that the CDM assumption holds gives unbiased estimates of intervention effect regardless of whether the missingness mechanism is the same or different between the intervention groups, and whether there is an interaction between intervention and baseline covariates in the data generating model for outcome, provided that such interaction is included in the model when required. There is no gain in terms of bias or efficiency of the estimates using MMI over CRA as long as both approaches use the same functional form of the same set of baseline covariates. Binary outcomes: The adjusted cluster-level estimator for estimating risk ratio (RR) using full data is consistent if the true data generating model is a log link model, the functional form of the baseline covariates is the same between the intervention groups, and the random effects distribution is the same between the intervention groups.<br>Cluster-level analyses using CRA for estimating risk difference (RD) are in general biased. For estimating RR, cluster-level analyses using CRA are valid if the true data generating model has log link and the intervention groups have the same missingness mechanism and the same functional form of the covariates in the outcome model. In contrast, MMI followed by cluster-level analyses gives valid inferences for estimating RD and RR regardless of whether the missingness mechanism is the same or different between the intervention groups, and whether there is an interaction between intervention and baseline covariate in the outcome model, provided that such interaction is included in the imputation model when required. In the case of individual-level analysis, both random effects logistic regression (RELR) and generalised estimating equations (GEE) give valid inferences using both CRA (adjusted for covariates such that the CDM assumption holds) and MMI regardless of whether the missingness mechanism is the same or different between the intervention groups, and whether there is an interaction between intervention and baseline covariate in the outcome model, provided that such interaction is included in both the imputation model and the analysis model when required.
3
Mollison, Jill. "Use of cluster randomised trials in implementation research." Thesis, University of Aberdeen, 2002. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU602063.
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Background. Implementation research is the scientific study of methods to promote the uptake of research findings in clinical practice. Cluster randomised trials are commonly adopted in implementation research, where interventions are generally targeted at health professionals or policymakers, in order to protect against contamination that would occur if individual patients were randomised. The application of cluster randomisation has important implications for design and analysis of trials evaluating implementation strategies. Case study: The Urological referral guidelines evaluation (URGE) has been used throughout this thesis, to explore the design and analysis issues of adopting a cluster randomised trial design in implementation research. URGE aimed to evaluate the effectiveness and efficiency of a guideline-based open access urological investigation service. This cluster randomised study adopted a 2X2 balanced incomplete block (BIB) design and collected data both prior to and following introduction of the intervention. The unit of randomisation was general practice and patients were recruited upon referral to secondary care. Aim: To investigate the implications of cluster randomisation for the design and analysis of trials evaluating implementation strategies. Objectives: This thesis has four distinct components. 1. A review of published cluster randomised trials in the field of implementation research. The methodological quality of these studies is assessed (Chapter 2). 2. An exploration of clustering within the URGE trial. Estimates of clustering and the imprecision in these estimates are considered for a number of endpoints, including process and outcome of care indicators and costs (Chapters 4 and 7). 3. The application of statistical methods in the analysis of cluster randomised trials. A number of approaches to the analysis of cluster randomised trials are described, applied and compared empirically. Incorporation of the BIB design and pre-intervention performance are also considered (Chapters 5 and 6). 4. Analysis of cost data collected from the economic evaluation conducted within the URGE trial. The analysis of skewed cost data collected within a cluster randomised trial design is considered (Chapter 7).
4
Wright, Neil D. "Choosing covariates in the analysis of cluster randomised trials." Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9017.
Full textAbstract:
Covariate adjustment is common in the analysis of randomised trials, and can increase statistical power without increasing sample size. Published research on covariate adjustment, and guidance for choosing covariates, focusses on trials where individuals are randomised to treatments. In cluster randomised trials (CRTs) clusters of individuals are randomised. Valid analyses of CRTs account for the structure imposed by cluster randomisation. There is limited published research on the e ects of covariate adjustment, or guidance for choosing covariates, in analyses of CRTs. I summarise existing guidance for choosing covariates in individually randomised trials and CRTs, and review the methods used to investigate the e ects of covariate adjustment. I review the use of adjusted analyses in published CRTs. I use simulation, analytic methods, and analyses of trial data to investigate the e ects of covariate adjustment in mixed models. I use these results to form guidance for choosing covariates in analyses of CRTs. Guidance to choose covariates a priori and adjust for covariates used to stratify randomisation is also applicable to CRTs. I provide guidance speci c to CRTs using linear and logistic mixed models. Cluster size, the intra-cluster correlations (ICCs) of the outcome and covariate, and the strength of the relationship between the outcome and covariate in uence the power of adjusted analyses and the precision of treatment e ect estimates. An a priori estimate of the product of cluster size and the ICC of the outcome can be used to assist choosing covariates. When this product is close to one, adjusting for a cluster level covariate or a covariate with a negligible ICC provide similar increases in power. For smaller values of this product, adjusting for a cluster level covariate gives minimal increases in power. The use of separate withincluster and contextual covariate e ect parameters may increase power further in some circumstances.
5
Martin, James Thomas. "Advancing knowledge in stepped-wedge cluster randomised controlled trials." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8034/.
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This thesis aims to extend the existing knowledge and enhance the methodological quality of future stepped-wedge cluster randomised trial (SW-CRTs). A systematic review of published SW-CRTs shows that pre-trial sample sizes calculations display a poor standard of reporting, with little adherence to published guidelines. The methodological rigor is often substandard, with inappropriate methods often used to determine sample size. In SW-CRTs, it is assumed that the correlation between observations is independent of the timing of them. We test the validity of this assumption by outlining a method to estimate the within-period and inter-period correlation. A case study illustrates what these correlations may look like in practice. The impact of varying cluster size in a SW-CRT is then demonstrated by comparing a design with unequal cluster size to a design with equal cluster size. A simulation study provides evidence that the SW-CRT is affected less, on average, than a P-CRT by varying cluster size. However, the potential power in a SW-CRT with unequal cluster sizes is extremely variable. A practical method for estimated power in a SW-CRT with varying cluster size is then illustrated through a Stata function.
6
Butcher, Isabella. "Design and analysis of cluster randomised trials for behavioural interventions." Thesis, Edinburgh Napier University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400594.
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7
Guarino, Peter David. "Consumer participation in the design of informed consent documentation for entry into randomised clinical trials : a cluster randomised trial." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422313.
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8
Thomson, Andrew. "Design and analysis issues in cluster randomised trials with binary outcomes." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498595.
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9
Ukoumunne, Obioha Chukwunyere. "Confidence intervals for the intraclass correlation coefficient in cluster randomised trials." Thesis, King's College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418293.
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10
Gomes, Manuel. "Statistical methods for cost-effectiveness analysis that use cluster-randomised trials." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2012. http://researchonline.lshtm.ac.uk/4646546/.
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This thesis considers alternative statistical methods for cost-effectiveness analysis (CEA) that use cluster randomised trials (CRTs). The thesis has four objectives: firstly to develop criteria for identifying appropriate methods for CEA that use CRTs; secondly to critically appraise the methods used in applied CEAs that use CRTs; thirdly to assess the performance of alternative methods for CEA that use CRTs in settings where baseline covariates are balanced; fourthly to compare statistical methods that adjust for systematic covariate imbalance in CEA that use CRTs. The thesis developed a checklist to assess the methodological quality of published CEAs that use CRTs. This checklist was informed by a conceptual review of statistical methods, and applied in a systematic literature review of published CEAs that use CRTs. The review found that most studies adopted statistical methods that ignored clustering or correlation between costs and health outcomes. A simulation study was conducted to assess the performance of alternative methods for CEA that use CRTs across different circumstances where baseline covariates are balanced. This study considered: seemingly unrelated regression (SUR) and generalised estimating equations (GEEs), both with a robust standard error; multilevel models (MLMs) and a non-parametric 'two-stage' bootstrap (TS8). Performance was reported as, for example, bias and confidence interval (Cl) coverage of the incremental net benefit. The MLMs and the TSB performed well across all settings; SUR and GEEs reported poor Cl coverage in CRTs with few clusters. The thesis compared methods for CEA that use CRTs when there are systematic differences in baseline covariates between the treatment groups. In a case study and further simulations, the thesis considered SUR, MLMs, and TSB combined with SUR to adjust for covariate imbalance. The case-study showed that cost-effectiveness results can differ according to adjustment method. The simulations reported that MLMs performed well across all settings, and unlike the other methods, provided Cl coverage close to nominal levels, even with few clusters and unequal cluster sizes. The thesis concludes that MLMs are the most appropriate method across the circumstances considered. This thesis presents methods for improving the quality ofCEA that use CRTs, to help future studies provide a sound basis for policy making.
11
Flynn, Terry Nicholas. "Design and analysis of randomised controlled trials : economic aspects of cluster randomisation." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393952.
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12
Eldridge, Sandra Mary. "Assessing, understanding and improving the efficiency of cluster randomised trials in primary care." Thesis, Queen Mary, University of London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422349.
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13
Campbell, Marion K. "Cluster randomised trials in implementation research : intracluster correlation coefficients, sample size and reporting considerations." Thesis, University of Aberdeen, 2003. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU176474.
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This thesis examines aspects of the application of the cluster randomised trial design in implementation research. In particular, it focuses on three main themes: a) the intracluster correlation coefficient (ICC) in cluster randomised trials of implementation research and factors affecting its magnitude; b) the impact of the ICC on sample size calculations; and c) reporting considerations for cluster randomised trials generally, and for ICCs in particular. The results show that empirical estimates of ICCs vary in size and certain factors - particularly the type of variable and the study setting - influence the magnitude of the ICC. When reporting an ICC, three aspects were found to be important: a) a description of the dataset, b) information on how the ICC was calculated; and c) information on the accuracy of the ICC. General reporting considerations for cluster randomised trials were also considered and found to require explanations for: a) the rationale for adopting a cluster design; b) how the effects of clustering were incorporated into the sample size calculations; c) how the effects of clustering were incorporated into the analysis; and d) the flow of both clusters and individuals through the trial, from assignment to analysis. A revised CONSORT statement accommodating the specific features of a cluster randomised trial was presented. The work outlined in this thesis shows that the adoption of a cluster randomised trial in implementation research has a number of important implications that researchers should consider when planning future trials.
14
Fiero, M., S. Huang, and M. L. Bell. "Statistical analysis and handling of missing data in cluster randomised trials: protocol for a systematic review." BMJ, 2015. http://hdl.handle.net/10150/617201.
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UA Open Access Publishing Fund.<br>Introduction: Cluster randomised trials (CRTs)
randomise participants in groups, rather than as
individuals, and are key tools used to assess
interventions in health research where treatment
contamination is likely or if individual randomisation is
not feasible. Missing outcome data can reduce power
in trials, including in CRTs, and is a potential source of
bias. The current review focuses on evaluating
methods used in statistical analysis and handling of
missing data with respect to the primary outcome in
CRTs.
Methods and analysis: We will search for CRTs
published between August 2013 and July 2014 using
PubMed, Web of Science and PsycINFO. We will
identify relevant studies by screening titles and
abstracts, and examining full-text articles based on our
predefined study inclusion criteria. 86 studies will be
randomly chosen to be included in our review. Two
independent reviewers will collect data from each study
using a standardised, prepiloted data extraction
template. Our findings will be summarised and
presented using descriptive statistics.
Ethics and dissemination: This methodological
systematic review does not need ethical approval
because there are no data used in our study that are
linked to individual patient data. After completion of
this systematic review, data will be immediately
analysed, and findings will be disseminated through a
peer-reviewed publication and conference presentation.
15
Bello, George. "Is it possible to improve the analytical approach to the evaluation of cluster-randomised trials where the complexity of the intervention demands a small number of clusters? : the case of the triage plus 'Integrated TB-HIV community intervention project in Lilongwe Rural, Malawi'." Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2014620/.
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Introduction In this thesis, analytical approaches for the design and evaluation of cluster randomised trials are presented and reviewed. In particular, statistical power/sample size issues relating to the design of cluster randomised trials for which only a limited number of clusters are available are assessed using a series of simulation studies. The use of computer simulation methods made it possible to investigate how well cluster randomised trials with limited numbers of clusters available can be optimised both in terms of statistical power and also the accuracy of parameter estimates. The study design conditions performing best in the simulation studies were then applied to a community intervention study involving informal healthcare providers: the 'Triage Plus integrated tuberculosis (TB) and human immuno-deficiency virus (HIV) community intervention project in Lilongwe rural, Malawi'. Aims and objectives The general aims of this dissertation were to: 1. investigate if it is possible to improve the analytical approach to the evaluation of cluster-randomised trials where the complexity of the intervention demands a small number of clusters and in which the primary outcome measure is a count of events occurring in a specified time interval; 2. investigate the effectiveness of engaging informal healthcare providers in integrated TB and HIV community intervention in treatment initiation rates and testing access rates, a cluster randomised trial was conducted in Malawi for which only a limited number of clusters were available to the researchers. The specific objectives were: 1. to review cluster randomised trials and the statistical methods used in the assessment of the effectiveness of the intervention in this type of trial when the primary outcome measure is a count of events occurring in a specified time interval; 2. to assess the statistical efficiencies of different design conditions in terms of statistical power and the accuracy of parameter estimates when determining the effectiveness of complex interventions with a limited number of clusters in this situation; iii 3. to identify the circumstances under which each of the statistical methods would be most robust in detecting significant intervention effects or providing accurate estimates of intervention effects; 4. to apply these statistical approaches to the data collected in the cluster randomised clinical trial of community based interventions for TB and HIV (the 'Triage Plus' study); 5. to assess the effect of involving non-paid informal healthcare providers in integrated TB and HIV community interventions aimed at improving testing and treatment initiation rates for these two diseases. Methods Two research approaches were used in this dissertation: 1. Simulation studies were used to investigate statistical efficiencies in terms of statistical power and accuracy in parameter estimation under different study design conditions for cluster randomised trials in which the primary outcome measure is a count of the number of events occurring during a specified period of time. 2. These statistical approaches were then applied to obtain robust estimates of the effect of the test intervention using the data collected during the “Triage Plus” study. The Triage Plus intervention, implemented in rural areas of Lilongwe, involved informal healthcare providers in an integrated TB and HIV community intervention. This intervention specifically involved empowering the informal healthcare providers in disease recognition, sputum specimen collection, referral of presumptive TB cases, and conducting community TB and HIV awareness meetings. Results The simulation studies showed that statistical efficiency and power both varied considerably under the different design conditions investigated. Non-coverage rates within the nominal value of 5% and negligible biases in the estimated fixed effects parameters (regression coefficients) were observed for all scenarios investigated including the (minimal) 3 cluster per arm design. However, it was discovered that, in order to achieve adequate power in low incidence disease conditions such as TB treatment initiation rates, more repeated measurement times were required to achieve adequate power of 80% with a true effect size of 20% or lower (for example, 12 measurement times were needed to achieve adequate power in this situation in a 3 cluster per arm design when the ICC was 0.00154). With an ICC of 0.081 iv at least 9 clusters were needed to achieve adequate statistical power of ≥80% with an effect size of 20% with 6 and 12 measurement time points respectively for high and low incidence disease conditions. For an effect size of 40%, at least 3 clusters per arm were needed to achieve adequate power with 4 repeated measurement times in low incidence diseases and 3 measurement times for high incidence diseases. For ICCs of 0.321 and above, no adequate statistical power was achieved with an effect size of ≤40% in both high and low disease incidence conditions. In the analysis of the TB services access data from the Triage plus study, the intervention significantly increased the number of presumptive TB cases accessing testing sites by 15.2% (p=0.003) in the first 12 months of the intervention; however, this was followed by a statistically non-significant reduction of 18.3% (p=0.224) when the intervention was rolled-out into the control clusters. Overall, the intervention was associated with a non-significant increase in TB treatment initiation rates of 18% (p=0.112). In the analysis of HIV services access rates, antiretroviral therapy (ART) initiation rates increased significantly by 34.7% (p=0.048) in the intervention clusters in the first 12 months of intervention, and the ART initiation rates were similar after rolling-out the intervention to the control clusters. Overall, the intervention was associated with a 61% increase in HIV testing uptake rates (p<0.001). Conclusion: To achieve adequate statistical power and improved precision in parameter estimation in cluster randomised trials with a count outcome measure, with the ICC of 0.00154 the simulation results suggested that a minimum of 3 clusters per arm is required with at least 12 measurement times for the estimation of an effect size of 20% (or higher) in low incidence disease situations. However, for high incidence outcomes, a minimum of 3 clusters per arm with 3 or more measurement times may be adequate to achieve a statistical power of at least 80%. For an ICC of 0.081, at least 3 clusters per arm were needed to achieve adequate power if the effect size was 40% after 4 repeated measurement times in low incidence diseases and 3 measurement times for high incidence diseases. With ICCs of 0.321 and above, no adequate statistical power was achieved with an effect size of ≤40% in both high and low disease incidence conditions. For the TB and HIV interventions in the “Triage Plus” study, engaging informal health care providers was clearly effective in improving TB and HIV testing uptake as well as ART v initiation. This reinforces the need for community participation in integrated TB and HIV interventions to combat the two diseases. However, for these providers to be effective in promoting TB treatment initiation, the number of sites offering TB testing and treatment initiation in rural areas should be increased to make them more accessible to the population.
16
Vaillant-Roussel, Hélène. "Education thérapeutique et insuffisance cardiaque en médecine générale." Thesis, Clermont-Ferrand 1, 2016. http://www.theses.fr/2016CLF1MM13/document.
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La Société Européenne de Cardiologie recommande pour les patients insuffisants cardiaques, en plus de la prise en charge médicamenteuse et interventionnelle, une prise en charge de type « éducation du patient » pour améliorer leur qualité de vie. En France, des programmes multidisciplinaires d’éducation du patient en hôpital ont mesuré leurs effets sur les ré-hospitalisations, la mortalité et le taux de participation des patients aux programmes. Certaines études internationales ont mesuré l’effet de programmes éducatifs délivrés par des équipes hospitalières multidisciplinaires, d’autres ont recruté des patients en soins primaires, mais les programmes étaient conduits par des infirmières ou des assistants des médecins généralistes. Ce type de programme ne reflète pas la situation actuelle en France où la plupart des patients sont suivis en ambulatoires par leurs médecins généralistes. Il semblait nécessaire de connaître plus précisément l'effet de programmes d'éducation du patient délivrés par les médecins généralistes auprès de leurs propres patients. L’objectif principal de l’étude ETIC (Education thérapeutique des patients insuffisants cardiaques) était d’évaluer si un programme d’éducation des patients insuffisants cardiaques délivré par leurs médecins traitants et suivis en médecine générale, améliorait leur qualité de vie. Cette étude interventionnelle, contrôlée, randomisée en grappes, a inclus 241 patients insuffisants cardiaques chroniques suivis par 54 médecins généralistes pendant 19 mois. Les médecins généralistes du groupe intervention ont été sensibilisés pendant 2 jours au programme d’éducation du patient et entrainés à adapter leurs propres objectifs d'éducation aux attentes du patient. Plusieurs séances d'éducation ont été simulées au cours de la formation des médecins. La 1re séance comportait un bilan éducatif explorant le mode de vie et les habitudes alimentaires, l'activité physique, les activités de loisirs, les projets et les ressources des patients. Les patients bénéficiaient de 4 séances d’éducation tous les 3 mois pendant 12 mois puis d’une séance d’éducation de synthèse au 19e mois de suivi. Le critère d’évaluation principal était la qualité de vie mesurée par une échelle de qualité de vie générique, la MOS 36-Item Short Form Health Survey (SF-36), et par une échelle de qualité de vie spécifique de l’insuffisance cardiaque, le Minnesota Living with Heart Failure Questionnaire (MLHFQ). La moyenne d’âge des patients était 74 ans (± 10.5), 62% était des hommes, et leur fraction d’éjection ventriculaire gauche moyenne était de 49.3% ± 14.3%. A la fin du suivi, le score MLHFQ moyen dans les groupes intervention et témoin étaient respectivement 33.4 ± 22.1 versus 27.2 ± 23.3; p = 0.74, intra-cluster coefficient [ICC] = 0.11. A la fin du suivi, la moyenne des scores SF-36 mental et physique dans les groupes intervention et témoin étaient respectivement 58 ± 22.1 versus 58.7 ± 23.9 (p = 0.58, ICC = 0.01) et 52.8 ± 23.8 versus 51.6 ± 25.5 (p = 0.57, ICC = 0.01). Le nombre de patients insuffisants cardiaques à fraction d’éjection conservée (ICFEp) était de 93 (80.9%) dans le groupe intervention et de 94 (74.6%) dans le groupe témoin (p = 0.24). Une étude exploratoire a été réalisée pour décrire les traitements prescrits dans la population de cette étude : évaluation de l’adhésion des médecins généralistes aux recommandations pour les patients à fraction d’éjection réduite (ICFEr) et description des traitements prescrits aux patients ICFEp. Le programme d’éducation du patient délivré dans le cadre de l’étude ETIC, n’a pas fait la preuve d’une amélioration de la qualité de vie des patients. D’autres recherches sont nécessaires pour améliorer la qualité de vie de ces patients. Les stratégies et les méthodes d’éducation restent un champ de recherche à développer<br>The European Society of Cardiology guidelines recommend non-pharmacological management to improve patients’ quality of life. In France, patient education programs delivered by hospital multidisciplinary teams in outpatient clinics have been assessed for their impact in patients with heart failure (HF). Some international studies assessed patient education interventions for heart failure patients recruited in the hospital. These programs were delivered by hospital multidisciplinary teams. Others have recruited patients with heart failure in primary care but the patient education programs were delivered by nurses or general practitioner assistants. This does not reflect the situation of the majority of patients in France, most of whom are ambulatory and cared for by general practitioners (GPs). Therefore, more evidence is needed on the effect of patient education programs delivered by GPs. As GPs are the doctors closest to patients, we hypothesized that their patient education could improved the HF patients quality of life. The ETIC (Education thérapeutique des patients insuffisants cardiaques) trial aimed to determine whether a pragmatic education intervention in general practice could improve the quality of life of patients with chronic heart failure (CHF) compared with routine care. This cluster randomised controlled clinical trial included 241 patients with CHF attending 54 general practitioners (GPs) in France and involved 19 months of follow-up. The GPs in the intervention group were trained during an interactive 2-day workshop to provide a patient education program. Several patient education sessions were simulated during the 2-day workshop. Patients had a further four education sessions, at 4, 7, 10 and 13 months, followed by an overview session at 19 months. The primary outcome was patients’ quality of life, as measured by the MOS 36-Item Short Form Health Survey (SF-36), a generic instrument, and the Minnesota Living with Heart Failure Questionnaire (MLHFQ). The mean age of the patients was 74 years (± 10.5), 62% were men and their mean left-ventricular ejection fraction was 49.3% (± 14.3). At the end of the follow-up period, the mean MLHFQ scores in the Intervention and Control Groups were 33.4 ± 22.1 versus 27.2 ± 23.3 (p = 0.74, intra-cluster coefficient [ICC] = 0.11). At the end of the follow-up period, SF-36 mental and physical scores in the Intervention and Control Groups were 58 ± 22.1 versus 58.7 ± 23.9 (p = 0.58, ICC = 0.01) and 52.8 ± 23.8 versus 51.6 ± 25.5 (p = 0.57, ICC = 0.01), respectively. Patients with heart failure with preserved ejection fraction (HFpEF) in the intervention group and in the control group were respectively: 93 (80.9%) and 94 (74.6%) (p = 0.24). A comprehensive data set of this trial was used to assess the prescription behaviour of GPs: GP’s guideline adherence for pharmacotherapy of heart failure with reduced ejection fraction (HFrEF) patients and to describe pharmacotherapy of HFpEF patients. Conclusions Patient education delivered by GPs to elderly patients with stable heart failure in the ETIC program did not demonstrate an improvement in their quality of life compared with routine care. Further research on improving the quality of life of elderly patients with CHF in primary care is needed. Patient education strategies and methods, as well as relevant tools and adapted criteria used to assess them, remain a field of research to develop. This area of investigation will be the following of this work
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You, Zhiying. "Power and sample size of cluster randomized trials." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2009r/you.pdf.
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Sanders, Elizabeth A. "Multilevel Analysis Methods for Partially Nested Cluster Randomized Trials." UNIVERSITY OF WASHINGTON, 2012. http://pqdtopen.proquest.com/#viewpdf?dispub=3452760.
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Fiero, Mallorie H. "Statistical Approaches for Handling Missing Data in Cluster Randomized Trials." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/612860.
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In cluster randomized trials (CRTs), groups of participants are randomized as opposed to individual participants. This design is often chosen to minimize treatment arm contamination or to enhance compliance among participants. In CRTs, we cannot assume independence among individuals within the same cluster because of their similarity, which leads to decreased statistical power compared to individually randomized trials. The intracluster correlation coefficient (ICC) is crucial in the design and analysis of CRTs, and measures the proportion of total variance due to clustering. Missing data is a common problem in CRTs and should be accommodated with appropriate statistical techniques because they can compromise the advantages created by randomization and are a potential source of bias. In three papers, I investigate statistical approaches for handling missing data in CRTs. In the first paper, I carry out a systematic review evaluating current practice of handling missing data in CRTs. The results show high rates of missing data in the majority of CRTs, yet handling of missing data remains suboptimal. Fourteen (16%) of the 86 reviewed trials reported carrying out a sensitivity analysis for missing data. Despite suggestions to weaken the missing data assumption from the primary analysis, only five of the trials weakened the assumption. None of the trials reported using missing not at random (MNAR) models. Due to the low proportion of CRTs reporting an appropriate sensitivity analysis for missing data, the second paper aims to facilitate performing a sensitivity analysis for missing data in CRTs by extending the pattern mixture approach for missing clustered data under the MNAR assumption. I implement multilevel multiple imputation (MI) in order to account for the hierarchical structure found in CRTs, and multiply imputed values by a sensitivity parameter, k, to examine parameters of interest under different missing data assumptions. The simulation results show that estimates of parameters of interest in CRTs can vary widely under different missing data assumptions. A high proportion of missing data can occur among CRTs because missing data can be found at the individual level as well as the cluster level. In the third paper, I use a simulation study to compare missing data strategies to handle missing cluster level covariates, including the linear mixed effects model, single imputation, single level MI ignoring clustering, MI incorporating clusters as fixed effects, and MI at the cluster level using aggregated data. The results show that when the ICC is small (ICC ≤ 0.1) and the proportion of missing data is low (≤ 25\%), the mixed model generates unbiased estimates of regression coefficients and ICC. When the ICC is higher (ICC > 0.1), MI at the cluster level using aggregated data performs well for missing cluster level covariates, though caution should be taken if the percentage of missing data is high.
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DiGuiseppi, Carolyn Grace. "Cluster-randomised controlled trial of a smoke alarm give-away programme." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269760.
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Westwood, Greta Patricia. "Primary care genetics education and clinic location : a cluster-randomised trial." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/73394/.
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The rapid growth in genetics knowledge with a subsequent impact on the health of the population has and will continue to increase the demand for NHS clinical genetics services. It has been proposed that general practitioners (GPs) could manage patients at low genetic risk. However, GPs do not have either the knowledge level or the confidence unless support is provided. A primary care genetic counsellor-led clinical genetics service could potentially support GPs in appropriate referral and as emerging NHS policy is planning to shift some specialist services from secondary to primary care settings, would seem a suitable setting for patients, who are not ill, but seek genetic information. This cluster-randomised trial was designed to evaluate the impact of two genetic counsellor-led primary care interventions: education to improve GP referral rates, and clinics to improve the patient pathway. GPs in 73 general practices (clusters) were randomised to receive a case scenario based seminar (intervention) or not (control), and their referred patients to receive a primary (intervention) or secondary (control) care clinic appointment. Outcome measures included GP referral and clinic attendance rates (primary), appropriate cancer and case scenario referral rates, GP referral attitude, clinic waiting times, patient satisfaction, patient and NHS clinic costs and referral case management (secondary). GP overall referral rate was not significantly higher and there was no indication of difference in clinic attendance rates, between groups. GPs from educated practices made significantly more referrals of patients at moderate and high genetic risk, of developing cancer (P=0·035, RRR 2×36, 95% confidence interval 1·07 to 5·24). To attend a primary care clinic appointment cost patients £3·28 less (P=0·000; £3·60 v. 6·62, 95% confidence interval -£4·76 to -£1·79) and 19 minutes less travel time (P=0·000, 95% confidence interval -30·70 to -7·90) than those who attended a clinic appointment in secondary care. More non-cancer than cancer appointments achieved the NHS 13-week clinic waiting time target (P=0·000, 81% v. 19%). 62% of all GP referrals, and 80% of all cancer referrals were entirely managed by genetic counsellors within the 18-week NHS referral to treatment pathway target. This trial has demonstrated that genetic counsellors can 1) provide GP education and improve access to clinical genetics services for individuals at increased cancer genetic risk and, 2) manage both the majority of all patients referred by their GP and those referred with a cancer diagnosis, irrespective of referrer, in a clinic closer to their home than the secondary care clinic and with less patient cost.
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Dong, Ranran. "Stepped Wedge Cluster Randomized Controlled Trials for Three-Level Data: Design and Evaluation." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1514492341281384.
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Weir, Arielle. "Conducting Cluster Randomized Controlled Trials in Hospitals: Barriers and Enablers Assessment and Strategies to Facilitate Delivery." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41509.
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Background: Cluster randomized control trials (cRCTs) are useful for asking about system-level interventions compared to other types of clinical research design, however they present unique challenges with conduct and delivery. Numerous cRCTs in hospitals have encountered challenges and time delays in enrolling hospitals and launching the trials which contributes to research waste. While each cRCT has unique barriers and enablers to their conduct, it is important to understand and explore these factors at the general level of the cRCT itself. Previous literature has documented factors associated with successful cRCTs, however, these studies focused primarily on the statistical aspect, while neglecting to evaluate the delivery of the trial.
Objectives: The goal of this dissertation was to explore barriers and enablers to conducting cRCTs in hospitals, and to identify potential strategies that facilitate their delivery. This research was conducted to identify evidence and generate guidance for researchers aiming to conduct these trials. Specifically, the objectives were: 1) To explore the current knowledge and evidence surrounding the implementation of cRCTs in hospitals; 2) To explore from the perspective of the coordinating site, what influenced the delivery and hospital engagement of an ongoing cRCT, and what challenges were encountered; 3) To identify strategies to facilitate delivery of cRCTs in hospitals; 4) To systematically review reported recruitment strategies of healthcare facilities in cRCTs.
Methods: The dissertation employed multiple research methods. To address the first objective, a scoping review was performed of current literature related to hospitals in cRCTs. The second objective was addressed with a qualitative case study. Semi-structured interviews were carried out with six key members of the team to understand their perceptions of the delivery of the trial. For the third objective, a tool matching two implementation concepts (the Consolidated Framework for Implementation Research (CFIR)- Expert Recommendations for Implementing Change (ERIC) matching tool) was used to identify strategies targeted to address barriers and enablers to cRCT conduct identified in the first two studies. Lastly, a systematic review was performed to address the fourth objective, to identify reported strategies used for hospital engagement in cRCTs. The thesis was guided and analyzed using an over-arching implementation framework, CFIR, and an implementation strategies list, the ERIC compilation. This was done to allow comparability and synthesis of results between methodologies from the dissertation, and between the results from the studies and previous literature. Results: Several key CFIR domains were identified in the literature in the scoping review that were determined to being influential for conducting the cRCTs in hospitals: the adaptability to tailor the trial to each site; the engagement of opinion leaders, champions and formally appointed implementation leaders in the cRCT process as facilitators to conducting the trial; the lack of a site perceiving a relative priority for the trial or tension for change for the clinical field presenting barriers to conducting the cRCT; and limited available resources can present barriers to conducting the cRCT. The qualitative case study identified similar CFIR domains and constructs as potentially influential for cRCT conduct, including the emphasis on adaptability of trial, the importance of tension for change in the sites for accepting inclusion in the trial, the availability of resources, and the engagement of leaders. The CFIR-ERIC matching study identified strategies that may be used to overcome barriers and target enablers for cRCT delivery from CFIR domains and constructs identified in the first two studies. A list of strategies was generated, ranked by the number of many determinants for which the strategy was listed as a Level 1 strategy, then by how many determinants for which the strategy was listed as a Level 2 strategy. The top ERIC strategies that were endorsed as a Level 1 strategy for any or multiple CFIR domains were: 1) Identify and prepare champions, 2) Conduct local needs assessment, 3) Conduct educational meetings, 4) Inform local opinion leaders, 5) Build a coalition, 6) Promote adaptability, 7) Develop a formal implementation blueprint, 8) Involve patients/consumers and family members, 9) Obtain and use patients/consumers and family feedback, 10) Develop educational materials, 11) Promote network weaving, 12) Distribute educational materials, 13) Access new funding, and 14) Develop academic partnerships. The systematic review identified literature reporting on the recruitment of healthcare facility sites into cRCTs. Numerous strategies for cRCT site recruitment were identified, and these were coded to the ERIC compilation. Strategies that were commonly cited were: involve executive boards, promote network weaving, conduct educational meetings, inform local opinion leaders, and centralize technical assistance.
Conclusions: The results from the dissertation can contribute to the knowledge for facilitating cRCT delivery in hospitals while recognizing the critical limitations in the studies. Key concepts and strategies to facilitate the conduct and delivery of cRCTs in hospitals were identified. Future research should aim to empirically evaluate the identified strategies. Researchers should aim to address the reporting gap for cRCT delivery identified by this dissertation.
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Stephens, Alisa Jane. "Enhancing Statistician Power: Flexible Covariate-Adjusted Semiparametric Inference for Randomized Studies with Multivariate Outcomes." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10449.
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It is well known that incorporating auxiliary covariates in the analysis of randomized clinical trials (RCTs) can increase efficiency. Questions still remain regarding how to flexibly incorporate baseline covariates while maintaining valid inference. Recent methodological advances that use semiparametric theory to develop covariate-adjusted inference for RCTs have focused on independent outcomes. In biomedical research, however, cluster randomized trials and longitudinal studies, characterized by correlated responses, are commonly used. We develop methods that flexibly incorporate baseline covariates for efficiency improvement in randomized studies with correlated outcomes. In Chapter 1, we show how augmented estimators may be used for cluster randomized trials, in which treatments are assigned to groups of individuals. We demonstrate the potential for imbalance correction and efficiency improvement through consideration of both cluster- and individual-level covariates. To improve small-sample estimation, we consider several variance adjustments. We evaluate this approach for continuous and binary outcomes through simulation and apply it to the Young Citizens study, a cluster randomized trial of a community behavioral intervention for HIV prevention in Tanzania. Chapter 2 builds upon the previous chapter by deriving semiparametric locally efficient estimators of marginal mean treatment effects when outcomes are correlated. Estimating equations are determined by the efficient score under a mean model for marginal effects when data contain baseline covariates and exhibit correlation. Locally efficient estimators are implemented for longitudinal data with continuous outcomes and clustered data with binary outcomes. Methods are illustrated through application to AIDS Clinical Trial Group Study 398, a longitudinal randomized study that compared various protease inhibitors in HIV-positive subjects. In Chapter 3, we empirically evaluate several covariate-adjusted tests of intervention effects when baseline covariates are selected adaptively and the number of randomized units is small. We demonstrate that randomization inference preserves type I error under model selection while tests based on asymptotic theory break down. Additionally, we show that covariate adjustment typically increases power, except at extremely small sample sizes using liberal selection procedures. Properties of covariate-adjusted tests are explored for independent and multivariate outcomes. We revisit Young Citizens to provide further insight into the performance of various methods in small-sample settings.
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Chaudhry, Shazia Hira. "Challenges in the Ethical Conduct and Ethics Review of Cluster Randomized Trials: A Survey of Cluster Randomization Trialists." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/22880.
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Unique characteristics of cluster randomized trials (CRTs) complicate the interpretation of standard research ethics guidelines. Variable interpretation by research ethics committees may further complicate review and conduct. An international web-based survey was administered to corresponding authors of 300 randomly sampled CRT publications. We investigated ethics review and consent practices, investigator experiences with ethics review, and the perceived need for CRT-specific ethics guidelines. The response rate was 64%. Ethics review and consent were under-reported in publications. Ethics approval was obtained in 91%, and consent from individual and cluster level participants in 79% and 82% of trials. Consent varied by level of experimental intervention, data collection, and cluster size. Respondents cited variability among ethics committees (46%), and negative impacts of ethics review on their studies (38%). The majority perceived a need for ethics guidelines (73%), and guidance for ethics committees (70%). CRT-specific ethics guidelines are required to ensure practices meet ethical standards.
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Glaman, Ryan. "Comparing Three Approaches for Handling a Fourth Level of Nesting Structure in Cluster-Randomized Trials." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1011881/.
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This study compared 3 approaches for handling a fourth level of nesting structure when analyzing data from a cluster-randomized trial (CRT). CRTs can include 3 levels of nesting: repeated measures, individual, and cluster levels. However, above the cluster level, there may sometimes be an additional potentially important fourth level of nesting (e.g., schools, districts, etc., depending on the design) that is typically ignored in CRT data analysis. The current study examined the impact of ignoring this fourth level, accounting for it using a model-based approach, and accounting it using a design-based approach on parameter and standard error (SE) estimates. Several fixed effect and random effect variance parameters and SEs were biased across all 3 models. In the 4-level model, most SE biases decreased as the number of level 3 clusters increased and as the number of level 4 clusters decreased. Also, random effect variance biases decreased as the number of level 3 clusters increased. In the 3-level and complex models, SEs became more biased as the weight level 4 carried increased (i.e., larger intraclass correlation, more clusters at that level). The current results suggest that if a meaningful fourth level of nesting exists, future researchers should account for it using design-based approach; the model-based approach is not recommended. If the fourth level is not practically important, researchers may ignore it altogether.
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Lowrie, Richard. "A cluster randomised controlled trial of Pharmacist-led Statin Outreach Support in Primary Care." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/3352/.
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Summary Background Elevated blood lipids (particularly cholesterol and sub-fractions) contribute to the risk of developing cerebral, peripheral and cardiovascular disease and associated complications which are leading causes of morbidity and death. Statins reduce the risk of suffering vascular events, with or without decreasing cholesterol levels. Statin prescribing continues to increase but there is scope to improve prescribing and dosing, particularly in primary care. However, there is insufficient empirical evidence to inform approaches to quality improvement. Methods Following pilot work, we designed a new model of primary care based pharmacist-led intervention for General Practitioners (GPs) and nurses. The aim of the intervention (called Statin Outreach Support, SOS) was to improve statin prescribing by GPs, in line with recent evidence, targeting patients at highest risk of suffering a vascular event. Eleven trained pharmacists worked in SOS allocated practices one day per week for a year. During this period, the pharmacist met three times with all GPs, all nurses and other practice staff. Between meetings, pharmacists used patient level clinical and prescribing data to identify eligible patients and help practices initiate, up-titrate the dose or switch to simvastatin 40mg where indicated. The effectiveness of SOS was tested in a prospective single blind cluster randomised controlled trial. Usual care (UC) practices received no pharmacist support during the study. With a mean of 1.7 years follow up, the study had over 90% power (at 5% significance) to detect a difference of 12% in the proportion of patients with controlled cholesterol after practices had received the SOS intervention. Results Thirty one practices were recruited from the UK’s largest Health Board area. At randomisation, 16 practices were allocated to the SOS intervention and 15 to UC with 4,040 patients included at baseline. Recruited practices showed few differences compared with invited, non participating practices. Practices and patients randomised to each arm of the study had similar distributions with respect to age, complications, cholesterol levels and statin prescribing. The mean age was 68 years; 53% male, 45% ischaemic aetiology. Fifty nine percent had no statin prescribed at baseline; only 51% had cholesterol controlled. Follow up included 7586 patients in 29 practices (one practice had disbanded between recruitment and randomisation and another practice dropped out). Compared with UC, the SOS intervention achieved the primary endpoint of increasing the proportion of patients prescribed Simvastatin 40mg with controlled cholesterol (SOS 44.9% vs. UC 27.9%; odds ratio 1.79 (95% CI: 1.61, 1.98), p< 0.001). Secondary endpoints were also improved in the SOS arm practices. The intervention effect was strong and consistent across most subgroups including a positive impact on patients from practices in areas of greater socioeconomic deprivation. Conclusion A pragmatic, new, complex intervention was developed, tested and shown to be effective in a cluster randomised controlled trial with good internal and external validity. If implemented on a wider scale, in practices with comparable characteristics and baseline prescribing, the SOS intervention has the potential to reduce the burden of vascular events for patients with vascular disease. This work provides a convincing evidence base for the role of pharmacists collaborating with primary care practices, to improve statin prescribing and drug based cholesterol management, for patients at highest risk of suffering vascular events.
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Sikander, Khawaja Siham. "A Cluster Randomised Trial of a Psychosocial Intervention for Perinatal Deppression in Rural Pakistan." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503736.
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Jokhio, Abdul Hakeem. "A cluster randomised controlled trial of reorganising maternal health care services in Sindh, Pakistan." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390759.
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A community-based randomised controlled trial was conducted in the district Larkana of Sindh province of Pakistan. The new model was based on reorganising the existing maternal health services. Three sub-districts were randomly assigned to the intervention group and four to the control group. The intervention consisted of integrating traditional birth attendants with the health care system, the use of safe delivery packs and the provision of antenatal care by doctors. Over one year 19,525 women were recruited and followed up. The proportion of referrals was higher in the intervention group (10.0 Vs 6.9 %; odds ratio 1.50 [95% Cl 1.26-1.74]). Significant differences were also found in some pregnancy complications including haemorrhage, obstructed labour and puerperal sepsis. Perinatal mortality in the intervention group was 83, compared to 118 per 1000 births for the control group, odds ratio 0.69 (95% Cl 0.53-0.85)(P<O.OOI). Maternal mortality ratio was also lower in the intervention group (303 Vs 439 per 100,000 live births), but this reduction did not achieve statistical significance (odds ratio 0.74,95% C I 0.23-1.24). Implementation of such a model could significantly improve the effectiveness of maternal health services in rural settings in Pakistan.
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Ackatia-Armah, Robert Samuel. "Community-based management of acute malnutrition in Malian children: a cluster randomized trial." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12704.
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Thesis (Ph.D.)--Boston University
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.<br>Acute malnutrition (AM), characterized by wasting, affects 55 million children under five years of age in developing countries. In Mali, the prevalence of AM exceeds 15% in some seasons. There is currently no consensus on the most effective dietary treatment strategy for children with moderate AM (MAM).
Twelve health centers in rural Mali were randomly assigned to provide children with MAM (defined as mid-upper arm circumference (MUAC) < 12.5 and ≥ 11.0 cm or weight-for-length Z-score (WLZ) <-2.0 WHO standard and >70% NCHS reference median) 1 of 4 dietary regimens: 1) lipid-based, ready-to-use supplementary food (Supplementary Plumpy, SP); 2) special corn soy blend for MAM (CSB++); 3) locally processed, fortified food (Misola, MI); or 4) locally milled flours (millet and cowpea) plus oil, sugar and micronutrient powder (HFM). 1264 non-edematous children aged 6-35 months with MAM were offered ~500 kcal/d of assigned diet in addition to their usual food intake for 12 weeks. Hemoglobin (Hb) was measured in 1154 children, and plasma ferritin and transferrin receptor were measured in a subset of 452 children.
1178 children (93.2%) completed the study and attendance at weekly/bi-weekly follow-up visits was >85% in all groups. The adjusted mean (95% CI) change in weight in kg from baseline was greater with SP and CSB++ than other regimens (1.16 (1.08, 1.24), 1.04 (0.96, 1.13), 0.91 (0.82, 0.99), 0.83 (0.74, 0.92) for the respective study groups, p<0.001 ANOVA). MUAC changes followed a similar pattern. For length, SP and CSB++ differed significantly from HFM only. Recovery from MAM (defined as WLZ>-2.0, MUAC> 12.5cm) was higher with SP than the three other regimens (73%, 68%, 61%, 58% respectively, p less than O.OOO1). Total cost per treatment based on median time to recovery was $2.20 for SP, $1.43 for CSB++, $1.83 for MI and $1.65 for HFM. Anemia rates remained high (>81 %) in all groups after treatment. SP generally provided greater improvement in iron status compared to MI while CSB++ and HFM had intermediate effects.
SP was more effective than other dietary regimens for the treatment of MAM and improvement of iron status; however, the benefits must be considered in relation to product costs and availability.
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Shen, Zuchao. "Optimal Sample Allocation in Multilevel Experiments." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553528863915366.
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Vincent, Brenda. "Quantifying Power and Bias in Cluster Randomized Trials Using Mixed Models vs. Cluster-Level Analysis in the Presence of Missing Data: A Simulation Study." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/613376.
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In cluster randomized trials (CRTs), groups are randomized to treatment arms rather than individuals while the outcome is assessed on the individuals within each cluster. Individuals within clusters tend to be more similar than in a randomly selected sample, which poses issues with dependence, which may lead to underestimated standard errors if ignored. To adjust for the correlation between individuals within clusters, two main approaches are used to analyze CRTs: cluster-level and individual-level analysis. In a cluster-level analysis summary measures are obtained for each cluster and then the two sets of cluster-specific measures are compared, such as with a t-test of the cluster means. A mixed model which takes into account cluster membership is an example of an individual-level analysis. We used a simulation study to quantify and compare power and bias of these two methods. We further take into account the effect of missing data. Complete datasets were generated and then data were deleted to simulate missing completely at random (MCAR) and missing at random (MAR) data. A balanced design, with two treatment groups and two time points was assumed. Cluster size, variance components (including within-subject, within-cluster and between-cluster variance) and proportion of missingness were varied to simulate common scenarios seen in practice. For each combination of parameters, 1,000 datasets were generated and analyzed. Results of our simulation study indicate that cluster-level analysis resulted in substantial loss of power when data were MAR. Individual-level analysis had higher power and remained unbiased, even with a small number of clusters.
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Evans, Charlotte Elizabeth Louise. "A cluster randomised controlled trial to improve primary school children's packed lunches in the UK." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.530836.
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Sarkar, B. K. "A cluster randomised trial of a brief tobacco cessation intervention in low income communities in India." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1426103/.
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Each year, tobacco use is estimated to contribute to 5.4 million deaths worldwide. There is an urgent need to develop and evaluate affordable, practicable and scalable interventions to promote cessation of tobacco use. This thesis describes a pragmatic, two-arm, community-based cluster randomised controlled trial of a brief pro-active tobacco cessation intervention focused on adult tobacco users in low-income communities. First a census survey of 30,655 adults was conducted in selected administrative blocks of low income urban communities in Delhi. This assessed tobacco use prevalence and identified tobacco users eligible to take part in the randomised controlled trial. The main study was a cluster randomised controlled trial with two arms. The intervention arm was a brief intervention comprising pro-active advice to quit to all tobacco users initiated by visiting their home, advice on how to quit and a short session of training in craving reduction using simple yogic breathing exercises (BA-YBA). The control condition involved very brief advice on tobacco cessation (VBA). A total of 1,214 participants consented to take part. The primary outcome measure was self-reported abstinence for the preceding 6 months assessed 7 months after the intervention, validated by salivary cotinine concentration, with those lost to follow up considered as continuing tobacco users. The primary analysis was by logistic regression adjusting for clustering. The follow-up rate at 7 months was 95.1% and similar in the intervention and control arms. The quit rate by the primary outcome measure was 2.6 percent versus 0.5 percent in the control group (OR 5.36 CI 1.13-25.45, P=0.02). The effect size in terms of percentage point difference was similar to that found in the Cochrane review of brief interventions for smoking cessation but the odds ratio was much higher. On the basis of these findings and others in the literature, serious consideration should be given to delivery of brief tobacco cessation advice via outreach in low income communities in India.
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Kime, Stuart James Martin. "Student evaluation of teaching : can it raise attainment in secondary schools? : a cluster randomised controlled trial." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12267/.
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The effectiveness of teaching is cited as one of the most significant actors on students’ learning (Centra, 1993; Creemers, 1994; Marsh, Nagengast, Fletcher, & Televantou, 2011), yet the measurement of it is an imperfect and problematic activity, not least due to the lack of consensus over a definition of effective teaching and, consequently, no consistently-used measurement instrument(s) designed for the purpose (Chingos & Peterson, 2011; Goldhaber & Anthony, 2004; Kane, McCaffrey, Miller, & Staiger, 2013). This thesis describes a study designed to validate an instrument intended to capture secondary school students’ evaluation of teaching (SET) ratings in 36 UK schools during the 2012-13 academic year, and a randomised controlled trial (RCT) to evaluate the impact on student progress of a peer-coached consultative feedback intervention for teachers. The thesis concludes that the SecondarySEEQ instrument is valid and reliable for the purpose of capturing AS and A Level students’ perceptions of the quality of teaching they receive from their teachers, a finding which adds weight to the case for SETs as a useful component of a diagnostic feedback system for teachers. I also conclude that the peer-coached intervention had a no detectable effect on student outcomes.
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Solomon, Emma Louise. "The Devon Active Villages Evaluation (DAVE) trial of a community-level physical activity intervention in rural south-west England : a stepped wedge cluster randomised controlled trial." Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/14802.
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Background: Although physical inactivity has been linked with numerous chronic health conditions and overall mortality, the majority of English adults report insufficient physical activity. To increase population physical activity levels, researchers have called for more community-level interventions. To evaluate these complex public health interventions, innovative study designs are required. The aim of this thesis was to evaluate whether a community-level physical activity intervention—‘Devon Active Villages’—increased the activity levels of rural communities. Methods: The Devon Active Villages intervention provided villages with 12 weeks of physical activity opportunities for all age groups. Community engagement helped tailor activity programmes for each village; communities were then supported for a further 12 months. 128 rural villages from south-west England were randomised to receive the intervention in one of four time periods, as part of a stepped wedge cluster randomised controlled trial. Data collection consisted of a postal survey of a random sample of adults (≥18 years), at baseline, and after each of the four intervention periods. The primary outcome of interest was the proportion of adults who reported sufficient physical activity to meet the current guidelines (≥150mins of moderate-and-vigorous, or ≥75mins of vigorous-intensity activity per week). The number of minutes spent in moderate-and-vigorous activity per week was analysed as a secondary outcome. Using data from all five periods, a comparison of study outcomes between intervention and control arms was performed, allowing for time period (as a fixed effect), and the random effect induced by correlation of outcomes (clustering) within villages. Additionally, the baseline data were analysed separately using logistic and linear regression models to examine the correlates of physical activity behaviour in rural adults. Results: Baseline study: 2415 adults completed the postal survey (response rate 37.7%). The following factors both increased the odds of meeting the recommended activity guidelines and were associated with more leisure-time physical activity: being male, in good health, greater commitment to being more active, favourable activity social norms, greater physical activity habit, and recent use of recreational facilities. In addition, there was evidence that younger age, lower body mass index, having a physical occupation, dog ownership, inconvenience of public transport, and using recreational facilities outside the local village were associated with greater reported leisure-time physical activity. Main study: 10,412 adults (4693 intervention, 5719 control) completed the postal survey (response rate 32.2%). The intervention did not increase the odds of adults meeting the physical activity guideline, although there was weak evidence of an increase in the minutes of moderate-and-vigorous-intensity activity per week. The ineffectiveness of the intervention may have been due to its low penetration—only 16% of intervention participants reported being aware of the intervention, and just 4% reported participating in intervention events. Conclusions: Baseline study: This study highlights potentially important correlates of physical activity that could be the focus of interventions targeting rural populations, and demonstrates the need to examine rural adults separately from their urban counterparts. Main study: A community-level physical activity intervention providing tailored physical activity opportunities to rural villages did not improve physical activity levels in adults. Greater penetration of such interventions needs to be achieved for them to have any chance of increasing the prevalence of physical activity at the community level.
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Hammersley, Victoria Suzan. "Impact of health care professional training on adolescent hay fever : cluster randomised controlled trial of a complex intervention in primary care." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/15904.
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Background Hay fever is typically poorly managed, particularly in adolescents, in whom it is responsible for considerable morbidity and impairment in educational performance. Evidence-based training of professionals has the potential to improve outcomes, but it can be expensive and so warrants formal evaluation. This trial sought to evaluate the effectiveness of a training intervention for primary care-based health care professionals on adolescent disease-specific quality of life. Methods A cluster randomised controlled trial was conducted in UK general practices. Practices were centrally randomised to a short, intensive training course on the evidence-based management of hay fever (intervention arm) or distribution of guidelines (control arm). The primary outcome measure was the change in the validated Rhinoconjunctivitis Quality of Life Questionnaire with Standardized Activities (RQLQ(S)) score in adolescents with hay fever between baseline and six weeks post-intervention (minimal clinically important difference = 0.5). Secondary outcome measures included health care professionals’ knowledge and confidence in managing hay fever, number of hay fever-related consultations, relevant treatments prescribed and symptom scores. Multi-level modelling using a random effects model was used to take account of between and within cluster variation, adjusting for strata, individual covariates and year of study. Results Thirty-eight general practices were randomised (20 in the intervention arm) and 246/341 patients (50.2% male, mean age 15 years) were included in the primary outcome analysis. Health care professionals’ self-assessed knowledge and confidence improved (prescribing/recommending treatment mean score 95% CI 1.4, 2.8), and the training was perceived to be of value. This did not however result in clinically or statistically significant improvements in RQLQ(S): -0.15, 95% CI -0.52 to +0.21. There were no differences in consultation frequency (95% CI -0.02, +0.63), treatments issued for hay fever (95% CI -0.24, +0.08) or symptom scores (95% CI - 1.03, +0.54). Conclusions Although attendance on this short, intensive hay fever training course was associated with professionals’ increased self-assessed confidence and understanding of the clinical management of hay fever, this did not translate into improvements in disease-specific quality of life or reduction in rhinitis symptoms in adolescents with hay fever.
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Dinh, Thi Thuy Ha. "A Self-management program for people with heart failure in Hanoi, Vietnam : a cluster randomised controlled trial." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/101527/1/Thi%20Thuy%20Ha_Dinh_Thesis.pdf.
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This project examined teaching of heart failure self-management to both nurses and patients in Vietnam. The main study was an evidence-based clinical trial, revealing that a short individual self-care education intervention improved patients’ knowledge and adherence to recommended self-care behaviours. The thesis also highlighted that people often struggle to understand health information. It demonstrated that the teach-back method should be a priority strategy in delivering health education to those with low health literacy.
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Lutge, Elizabeth Eleanor. "Economic support to improve TB treatment outcomes in South Africa : a pragmatic cluster randomized controlled trial." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85667.
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Thesis (PhD)--Stellenbosch University, 2013.<br>ENGLISH ABSTRACT: This thesis focused on the provision of economic support to improve the outcomes of patients on TB treatment. Although the association between poverty and tuberculosis is generally acknowledged, there is little evidence to guide the use of economic interventions to improve tuberculosis control. In South Africa, a high burden country with extensive poverty, such evidence is particularly important.
The first part of this thesis is a Cochrane systematic review of evidence from randomized controlled trials regarding the effectiveness of economic support among patients with tuberculosis. Eleven trials were included: ten conducted among marginalised groups in the United States on economic support for people on prophylactic treatment for latent TB; and one from Timor-Leste on economic support for patients with active TB. The review found that the use of economic interventions in patients with latent TB may increase the return rate for reading tuberculin skin test results, probably improves clinic re-attendance for initiation or continuation of prophylaxis and may improve completion of prophylaxis, compared to normal care. However, it is uncertain if economic support improves treatment completion in patients with active TB (low quality evidence).
The second part of the thesis reports the findings of a pragmatic, cluster randomized controlled trial to evaluate the feasibility and effectiveness of delivering economic support to patients on treatment for active TB in South Africa. Patients with drug sensitive pulmonary TB were offered a monthly voucher valued at ZAR120 until completion of treatment or a maximum of eight months. Patients in control clinics received usual TB care. A parallel process evaluation provided contextual information to explain the trial findings. The qualitative component of this evaluation consisted of in-depth interviews with a sample of trial participants, including patients, nurses and health managers, to assess responses to the voucher and its administration. The quantitative component included a survey of patients’ household expenditure to assess patients’ levels of poverty and the effects of the voucher on these, and an analysis of the goods on which patients spent their vouchers.
4091 patients were included in the trial: 1984 in the control arm (10 clinics) and 2107 in the intervention arm (10 clinics). Intention to treat analysis showed a small but non-significant improvement in treatment success rates in intervention clinics (intervention 76.2%; control 70.7%; risk difference 5.6% (-1.2; 12.3%), p = 0.107). Fidelity to the intervention was low, partly because nurses preferred to issue vouchers based on perceived financial need, rather than on eligibility. Logistical difficulties in delivering vouchers to clinics also undermined fidelity. The vouchers did not significantly increase patients’ household expenditure, but were experienced by patients as helpful, especially in providing more food with which to take their tablets.
Factors related to the administration of economic support may undermine its effectiveness in improving TB treatment outcomes. Further research is needed to explore how best to deliver such economic support to those eligible to receive it, particularly in low and middle income countries where the burden of tuberculosis is highest.<br>AFRIKAANSE OPSOMMING: Hierdie tesis was toegespits op die verlening van ekonomiese steun om die uitkomste van pasiënte op tuberkulose- (TB-) behandeling te verbeter. Hoewel die verband tussen armoede en TB in die algemeen erken word, is daar nie veel bewyse om die gebruik van ekonomiese intervensies ter verbetering van TB-beheer te staaf nie. In Suid-Afrika – ’n land met ’n hoë TB-las en wydverspreide armoede – is sulke bewyse veral belangrik.
Die eerste deel van hierdie tesis behels ’n sistematiese Cochrane-oorweging van bewysmateriaal afkomstig van verewekansigde, gekontroleerde proewe oor die doeltreffendheid van ekonomiese steun aan pasiënte met tuberkulose.
Altesame 11 proewe is ingesluit: Tien is gedoen onder gemarginaliseerde groepe in die Verenigde State met die fokus op ekonomiese ondersteuning aan mense wat profilaktiese behandeling vir latente TB ontvang het. Een, van Timor-Leste, was gefokus op ekonomiese ondersteuning aan pasiënte met aktiewe tuberkulose. Die ondersoek het aan die lig gebring dat, vergeleke met normale sorg, die gebruik van ekonomiese intervensies by pasiënte met latente tuberkulose tog die omdraaikoers vir die lees van tuberkulien-veltoetsresultate kan verhoog, waarskynlik hertoelating tot klinieke vir die inisiëring of voortsetting van profilakse verbeter, en die voltooiing van profilakse kan verbeter.
Die tweede gedeelte van die tesis behels ’n verslag oor die bevindings van ’n pragmatiese, trosverewekansigde gekontroleerde proef, om te bepaal hoe doenlik en doeltreffend dit sou wees om ekonomiese steun te verleen aan pasiënte wat in Suid-Afrika vir aktiewe tuberkulose behandel word. Pasiënte met middelsensitiewe pulmonêre tuberkulose het tot en met die voltooiing van hul behandeling, of tot ’n maksimum van agt maande, ’n maandelikse koopbewys ter waarde van ZAR120 ontvang. Pasiënte in kontroleklinieke het die gewone TB-sorg ontvang. ’n Parallelle prosesevaluering het kontekstuele inligting voorsien ter verklaring van die bevindinge van die proef. Die kwalitatiewe komponent van hierdie evaluering het bestaan uit diepte-onderhoude met ’n steekproef van alle deelnemers aan die proefneming, insluitend pasiënte, verpleegpersoneel en gesondheidsbestuurders, om hul reaksies te bepaal op die koopbewys self sowel as op die administrasie daarvan. Die kwantitatiewe komponent het ’n opname oor pasiënte se huishoudelike besteding ingesluit, ter vasstelling van hul armoedevlak en die moontlike uitwerking van die koopbewys daarop, asook ’n ontleding van die goedere waarop pasiënte hul koopbewyse bestee het.
Altesame 4 091 pasiënte is by die proef ingesluit – 1 984 in die kontrole-afdeling (10 klinieke) en 2 107 in die intervensie-afdeling (10 klinieke). ’n Voorneme-om-te-behandel- (ITT-) ontleding toon ’n klein dog nie-betekenisvolle verbetering in behandelingsuksessyfers in intervensieklinieke (intervensie 76,2%; kontrole 70,7%; risikoverskil 5,6% (-1,2; 12,3%), p = 0.107). Getrouheid aan die intervensie was laag – deels omdat verpleegkundiges verkies het om die koopbewyse op grond van veronderstelde finansiële behoeftigheid eerder as volgens die studiekriteria uit te deel. Die koopbewyse het nie pasiënte se huishoudelike besteding beduidend verhoog nie, maar pasiënte het dit wél as nuttig ervaar, veral omdat hulle daarmee meer kos kon koop om saam met hul pille in te neem.
Faktore wat verband hou met die administrasie van ekonomiese ondersteuning kan die doeltreffendheid van sodanige steun in die verbetering van TB-behandelingsuitkomste ondermyn. Verdere navorsing word vereis om te verken wat die beste manier sou wees om sodanige ekonomiese steun te bied aan diegene wat daarvoor in aanmerking kom, veral in lae- en middel-inkomstelande, waar die TB-las die hoogste is.
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Park, Misook. "Design and Analysis Methods for Cluster Randomized Trials with Pair-Matching on Baseline Outcome: Reduction of Treatment Effect Variance." VCU Scholars Compass, 2006. http://hdl.handle.net/10156/2195.
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Tanner, Whitney Ford. "Improved Standard Error Estimation for Maintaining the Validities of Inference in Small-Sample Cluster Randomized Trials and Longitudinal Studies." UKnowledge, 2018. https://uknowledge.uky.edu/epb_etds/20.
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Data arising from Cluster Randomized Trials (CRTs) and longitudinal studies are correlated and generalized estimating equations (GEE) are a popular analysis method for correlated data. Previous research has shown that analyses using GEE could result in liberal inference due to the use of the empirical sandwich covariance matrix estimator, which can yield negatively biased standard error estimates when the number of clusters or subjects is not large. Many techniques have been presented to correct this negative bias; However, use of these corrections can still result in biased standard error estimates and thus test sizes that are not consistently at their nominal level. Therefore, there is a need for an improved correction such that nominal type I error rates will consistently result.
First, GEEs are becoming a popular choice for the analysis of data arising from CRTs. We study the use of recently developed corrections for empirical standard error estimation and the use of a combination of two popular corrections. In an extensive simulation study, we find that nominal type I error rates can be consistently attained when using an average of two popular corrections developed by Mancl and DeRouen (2001, Biometrics 57, 126-134) and Kauermann and Carroll (2001, Journal of the American Statistical Association 96, 1387-1396) (AVG MD KC). Use of this new correction was found to notably outperform the use of previously recommended corrections.
Second, data arising from longitudinal studies are also commonly analyzed with GEE. We conduct a simulation study, finding two methods to attain nominal type I error rates more consistently than other methods in a variety of settings: First, a recently proposed method by Westgate and Burchett (2016, Statistics in Medicine 35, 3733-3744) that specifies both a covariance estimator and degrees of freedom, and second, AVG MD KC with degrees of freedom equaling the number of subjects minus the number of parameters in the marginal model.
Finally, stepped wedge trials are an increasingly popular alternative to traditional parallel cluster randomized trials. Such trials often utilize a small number of clusters and numerous time intervals, and these components must be considered when choosing an analysis method. A generalized linear mixed model containing a random intercept and fixed time and intervention covariates is the most common analysis approach. However, the sole use of a random intercept applies assumptions that will be violated in practice. We show, using an extensive simulation study based on a motivating example and a more general design, alternative analysis methods are preferable for maintaining the validity of inference in small-sample stepped wedge trials with binary outcomes. First, we show the use of generalized estimating equations, with an appropriate bias correction and a degrees of freedom adjustment dependent on the study setting type, will result in nominal type I error rates. Second, we show the use of a cluster-level summary linear mixed model can also achieve nominal type I error rates for equal cluster size settings.
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Campbell, Michelle Louise Churchill. "A Cluster Randomised Trial to Evaluate the Effectiveness of a Psychosocial Intervention for Teenagers in Reducing Discrimination about Psychosis." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503759.
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Christian, Meaghan Sarah. "Can a school gardening intervention improve children's fruit and vegetable intake? : an evaluation of two clustered randomised controlled trials." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/4956/.
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Background This thesis describes the findings from the first clustered randomised controlled trials (RCT) designed to evaluate if a school gardening programme, the Royal Horticultural Society (RHS) Campaign for School Gardening, has an effect on children’s fruit and vegetable intake. Methodology Primary schools from 8 London boroughs were invited to take part in one of two related RCTs. Trial 1 consisted of 23 schools; randomised into either the RHS-led or the Teacher-led intervention. Trial 2 consisted of 31 schools; randomised into either the Teacher-led or a comparison group. A 24-hour food diary (CADET) collected baseline and follow-up dietary intake. Questionnaires were designed to measure children’s knowledge and attitudes towards fruit and vegetables and assess intervention implementation. Results In Trial 1, 1256 children were randomised to receive either the RHS-led (n=529) or Teacher-led (n=727) intervention. Of these, 356 children from the RHS-led and 329 from the Teacher-led arm provided data for the primary analysis. In Trial 2, 1475 children were randomised to receive either the Teacher-led (n=756) or comparison (n=719) intervention. Of these, 488 children from the Teacher-led and 428 from the comparison arm provided data for the primary analysis. Baseline analysis of children’s fruit and vegetable intake showed that eating a family meal together, cutting up fruit and vegetables and parental modelling of fruit and vegetable intakes were all associated with higher intakes of fruit and vegetables in children. Results from the RCTs found that in Trial 1, for combined fruit and vegetable intake, the Teacher-led group had a higher mean change of 8 g (95%CI: -19, 36) compared to the RHS-led group -32 g (95%CI: -60, -3). However, after adjusting for possible confounders this difference was not significant (intervention effect: -40 g, 95%CI: -88, 1; p=0.06). In Trial 2, the Teacher-led group consumed on average 15 g (95%CI: -36, 148) more fruit and vegetables than the comparison group; this difference was not significant. No change was found in children’s knowledge and attitudes. The process measures revealed that if schools improved their RHS gardening score by 3 levels, children had on average an increase of 81 g of fruit and vegetables (95%CI: 0, 163; p=0.05) compared to schools that had no change in gardening score, after adjusting for confounders. Conclusion The primary analysis of these two trials has found very little evidence to support claims that school gardening alone can improve children’s fruit and vegetable intake. Only when a gardening intervention is implemented at a high level within the schools can it improve children’s fruit and vegetable intake.
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Milazi, Molly. "A bundled phosphate control intervention (4Ds) for adults with end stage kidney disease receiving haemodialysis: A cluster randomised controlled trial." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/198173/2/Molly_Milazi_Thesis.pdf.
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Hyperphosphataemia occurs in end-stage kidney disease and is managed by diet, drinks, drugs, and dialysis. Adherence to the 4Ds is challenging for patients. This thesis reports a pragmatic randomised controlled trial that evaluated the effectiveness of an innovative educational intervention "Taking control of your phosphate with the 4Ds" to improve adherence to phosphate control in adults receiving haemodialysis. The 4Ds, a bundled self-management intervention, was effective in improving patient's confidence about phosphate control methods. Importantly, the intervention was brief and feasible for nurses to deliver during haemodialysis treatment.
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Quinn, David. "Fidelity Versus Flexibility: Effects and Moderators of Program Management Structures on Teacher and Student Outcomes in a Cluster-Randomized Trial." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:27112715.
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The questions of how to improve educational practice at scale, and what role scientific investigation can or should play in that endeavor, have been central to the enterprise of education research since its beginning (Dewey, 1929). In one approach, researchers produce evidence regarding the effects of standardized instructional procedures on student learning, and then school- and district leaders manage teachers’ faithful implementation of those procedures. In another approach, teachers are encouraged to use their expert judgment and flexibly apply research-based principles of effective instruction in order to meet students’ unique learning needs. While these contrasting frameworks have each been influential in research and practice, little empirical work exists comparing the relative effectiveness of each of these approaches in advancing outcomes of interest in varying contexts.
In the two separate studies that comprise this dissertation, I analyze data from a school-level cluster-randomized trial in which schools were randomly assigned to implement READS – a summer literacy intervention for elementary school students that includes school-based and home-based components – under a fidelity or flexibility management approach. In the first study, I investigate – and find evidence consistent with – the hypothesis that the optimal approach to educational program implementation may be a scaffolded management sequence, in which implementers first develop proficiency with a program through a fidelity phase of management, and then make program adaptations under a flexibility management phase. The second study is motivated by the growing body of theoretical and empirical work demonstrating the numerous ways in which teachers’ social capital affects school improvement efforts. In this study, I investigate the effects of management approach on outcomes related to teachers’ social capital. I find that the flexibility approach caused participants to form more intervention-related consultation ties and caused them to consult more frequently about instructional adaptation, as opposed to implementation. At the same time, the expansion of participants’ intervention-related networks under the flexibility approach may have been offset by participants’ shrinking consultation networks in instructional areas unrelated to the intervention. Both of these studies have implications for research on how school improvement initiatives are introduced and managed.
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Sipos, Attila. "Preparing the way for evidence based implementation : a pharmacoepidemiological study of antipsychotic prescribing practice informing the design of a cluster randomised trial." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411085.
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Habib-Mourad, Carla. "An intervention to promote healthy eating and physical activity in Lebanese school children : Health-E-PALS : a pilot cluster randomised controlled trial." Thesis, Durham University, 2013. http://etheses.dur.ac.uk/7322/.
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Aim and objectives: The purpose of this study was to develop, implement and evaluate the effectiveness of a multicomponent school-based intervention that focused on promoting healthy eating and physical activity with school children (aged 9 to 11 years) in Lebanon, in order to prevent childhood obesity. Methods: A school-based intervention adapted to the culture of Lebanese and Arab populations and based on the constructs of the Social Cognitive Theory was developed. The intervention consisted of three components: classroom curriculum, food service, family involvement. Eight schools were selected from two different communities (high and low socioeconomic status) in Beirut and were randomly assigned (by a toss of a coin) to either the intervention or control group. Students aged nine to eleven years in intervention schools were exposed to the intervention components for three months. Students in control schools received their usual school curriculum. Anthropometric measurements, questionnaires on determinants of behavioural change, eating and physical activity habits were completed by the students in both groups at baseline and post intervention. Focus group interviews were conducted with students, teachers and parents in intervention schools at the end of the study. Results: Changes were observed based on self-report measures. Daily breakfast intake increased significantly in the intervention group compared with the control group (3.5 times more p<0.001). Students in the intervention group reported consuming significantly less chips and sweetened drinks at post-test compared with controls (86% & 88% less respectively p<0.001). There was no difference in physical activity and screen time habits and no changes in BMI between groups at post intervention. Knowledge and self-efficacy scores increased for the intervention (+2.8 & 1.7 points respectively p<0.001) but not for the control group. Interview data from focus groups showed that the programme was generally well accepted; students benefited in a pleasurable way and made attempts to change their eating and physical activity habits. Limitations for better outcomes include the length of the programme and the school environment. Conclusion: “Health-E-PALS” (Healthy Eating and Physical Activity in Lebanese School children) is a promising innovative, theory-based, culturally sensitive intervention to promote Healthy Eating and Physical Activity in Lebanese school children with a regional perspective.
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Manu, Alexander Ansah. "Newhints home visits cluster randomised controlled trial : impact on access to care for sick newborns and determinants, facilitators and barriers to this." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2012. http://researchonline.lshtm.ac.uk/768506/.
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Approximately 3.3 million (41 %) of global child deaths occur among children in the first 28 days of life (the neonatal period). Neonatal death reduction is imperative to achieving the 4th millennium development goal (MDG-4) which seeks to reduce global child deaths by two-thirds its levels in 1990 come 2015. Three direct causes: infections, asphyxia, and prematurity or low birthweight and its complications account for approximately 80% of these deaths, majority of which are preventable. Infection is the single most important cause in about a third (and up to half in high mortality settings) of all neonatal deaths. However, care seeking for sick newborns is generally poor and besieged by myriads of barriers with many newborn deaths occurring at home with no contact with health providers. Trials in south Asia have shown that prompt detection and treatment of newborn infections coupled with effective preventive measures can significantly reduce newborn deaths. The Ghana Newhints home visits cluster randomised controlled trial (CRT) is the first trial in sub-Saharan Africa to evaluate the impact of a community-based strategy on newborn care practices and neonatal mortality.
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Magoma, Moke Tito Myambita. "The effectiveness of antenatal birth plans in increasing skilled care at delivery and after delivery in rural Tanzania : a cluster randomised trial." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2010. http://researchonline.lshtm.ac.uk/682412/.
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Objective: To determine the effectiveness of ANC birth plans (birth preparedness and complication readiness) in increasing skilled care at delivery and after delivery Rationale: Although birth plans are key elements of focused ANC in many developing countries including Tanzania that aim to increase skilled care utilization at delivery, after delivery and during emergency obstetric complications, robust empirical evidence is lacking on their effectiveness. Methods The study was a cluster randomized controlled trial (RCT) that was conducted in Ngorongoro district, rural northern Tanzania. The primary outcome was the proportion of women who delivered at the available health units and the secondary outcomes were the proportion of women who sought postnatal care within one month of delivery and women's and providers' satisfaction with ANC. The study was implemented in three phases: the formative qualitative study that aimed to understand contextual factors for the high ANC care coverage but low utilization of health facilities for delivery and how the intervention could be implemented in the study district, a RCT to determine the effectiveness of the intervention in increasing skilled attendance at delivery and postpartum, and a process evaluation of the intervention and control arms' ANC. The qualitative study involved 15 focus group discussions, 12 key informant interviews and participant observation of the ANC and delivery care at randomly selected health units. Eight health units were randomly assigned to the intervention (antenatal care with an emphasis on birth plans by care providers) and an equal number to the control group (care as provided currently). A total of 905 consenting pregnant women (404 in the intervention arm and 501 in the control) at 24 weeks of gestation and above were recruited and followed up to the initial postnatal care clinic attendance or during the postnatal interview at home depending on which occurred first. Results Both demand and supply sides factors prevented women from utilizing health units for delivery and immediate postnatal care, despite the high level of ANC uptake. Notably, women's lack of planning for accessing delivery care at health units, norms and traditions dictating that home delivery is equally safe and health system deficiencies (structural, process and outcome) were the key barriers identified. 2 Unpaired t-test statistic was used to assess the effectiveness of the intervention on the primary and secondary outcomes taking into account the clustering effect. Overall, 34.8% of women in the intervention arm and 20.3% in the control delivered in the health facilities (difference in proportion: 14.5% [-9.4-38.3] p=0.2138 for the crude analysis and 16.8% [2.6-31.0] p=0.0248 for the adjusted analysis). Postnatal care utilization was 62.1% in the intervention and 32.1% in the control group (difference in proportion for the crude and adjusted analysis 30.0% [11.3-48.7] p=0.0040 and 31.3% [15.4-47.2] p=0.0009 respectively). Altogether, 96.8% of women in the intervention and 84.7% in the control units were satisfied with the ANC they received (difference in proportion: 12.1% [-6.3-30.5] p=0.1668 for the crude and 12.6% [-5.4-30.5] p=0.1454 adjusted analysis). Similarly, 97.9% and 91.0% of providers in the intervention and control arms were satisfied with the ANC they provided (difference in proportion: crude analysis 6.9% [-3.2-17.1] p=0.1547 and adjusted analysis 7.8% [-0.7-16.3] p=0.0688). Overall, the intervention was implemented as per study protocol. The average time for initial ANC consultation in the intervention arm of the study was 40.1 minutes (range 33-47 minutes) compared to 19.9 minutes (range 12-32 minutes) in the control arm p<0.0001. The average time for consultation during follow-up ANC visits was 23.3 minutes (rangel5-31) for the intervention units versus 10.3 minutes (range 6-17)in the control p=0.0001. Likewise, providers in the intervention units spent more time for counselling/health education or promotion than in the control units at both initial ANC attendance and during subsequent visits (average time at initial attendance 24.5 minutes, range 19-32 in the intervention vs 10.5 minutes, range 5-18 in the control arm) p<0.0001 ). The respective time for follow-up visits was 13.8 minutes (range 6-17) vs 4.5 minutes (range 0-10) p=0.0001. Nevertheless, the improvement was largely on the discussion on birth plans and PMTCT, and not on the other topics in the national focused ANC guidelines. Conclusion and implication for practice A well-implemented antenatal birth plan intervention improved women's utilization of health units for delivery, and post delivery without substantially affecting the women's and providers' satisfaction with ANC. Implementation of birth plans in health care settings in low resource settings like Ngorongoro is feasible and should be promoted as an effective strategy to increase skilled delivery and postnatal uptake.
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Nammontri, Orawan. "The effect of an intervention to enhance sense of coherence on oral health related quality of life : a cluster randomised controlled trial." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/2814/.
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Background: Psychological factors may influence oral health. One factor, sense of coherence (SOC) has been related to general and oral health, clinical status, oral health behaviours and oral health related quality of life (OHRQoL) in observational research with adults and children. Thus, improving SOC may be a way to improve OHRQoL. Aims of the study: To evaluate the effect of an intervention to enhance SOC on OHRQoL in children. Methods: Cluster randomised trial in twelve primary schools in Khonkaen, Thailand with 257 grade 5 students. Six schools were allocated randomly to the study and comparison groups respectively. Data included socio-demographic and clinical data. Self-report questionnaires assessed OHRQoL using the child perceptions questionnaire, CPQ11-14 and SOC with the 13-item SOC scale. Data were collected at three time points; at baseline, two weeks after the intervention and at 3 month follow up. Intervention: Seven 40-60 minute sessions over two months, focusing on child participation and empowerment. The first four sessions were classroom activities and included a mixture of didactic teaching, discussion, activities and games. The last three involved working on healthy school projects. The intervention was delivered by trained teachers who received an intensive one day course. Results: The two groups were similar for all variables at baseline. The intervention group had significant improvements in SOC and CPQ11-14 scores representing better OHRQoL at two weeks after the intervention and 3 month follow-up. SOC had a direct effect on symptoms and indirect effect on OHRQoL via symptoms. Conclusions: As well as providing experimental evidence that OHRQoL is determined by SOC, these data show that school-based interventions to enhance SOC may be a useful way to improve OHRQoL.