Academic literature on the topic 'Cox Proportional Hazard Ratio'
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Journal articles on the topic "Cox Proportional Hazard Ratio"
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Kropko, Jonathan, and Jeffrey J. Harden. "Beyond the Hazard Ratio: Generating Expected Durations from the Cox Proportional Hazards Model." British Journal of Political Science 50, no. 1 (2017): 303–20. http://dx.doi.org/10.1017/s000712341700045x.
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The Cox proportional hazards model is a commonly used method for duration analysis in political science. Typical quantities of interest used to communicate results come from the hazard function (for example, hazard ratios or percentage changes in the hazard rate). These quantities are substantively vague, difficult for many audiences to understand and incongruent with researchers’ substantive focus on duration. We propose methods for computing expected durations and marginal changes in duration for a specified change in a covariate from the Cox model. These duration-based quantities closely match researchers’ theoretical interests and are easily understood by most readers. We demonstrate the substantive improvements in interpretation of Cox model results afforded by the methods with reanalyses of articles from three subfields of political science.
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Fatmala, Siti Febriana, Mohamat Fatekurohman, and Alfian Futuhul Hadi. "PERBANDINGAN MODEL ACCELERATED FAILURE TIME DAN MODEL COX PROPORTIONAL HAZARD PADA KASUS KARDIOVASKULAR." Majalah Ilmiah Matematika dan Statistika 18, no. 1 (2018): 43. http://dx.doi.org/10.19184/mims.v18i1.17244.
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Cardiovascular disease is a disease that attacks the heart and blood vessels. Many types of cardiovascular diseases, but the most famous are coronary heart disease and stroke. Coronary heart disease is a disease that is the first cause of death that occurs in the world caused by risk factors and the length of time of survival of coronary heart disease patients, then using survival analysis with the Cox Proportional Hazard model and Accelerated Failure Time model. Comparison between Cox Proportional Hazard model and Accelerated Failure Time model expedited time can be determined by the survival time with a safe function, the hazard function and density function (comparison of income) of each questioned duration of time with the help of different AIC policies and the rate of deterioration. Estimation of the survival time of this cardiovascular case is determined from the Cox Proportional Hazard’s hazard ratio model and the Accelerated Failure Time’s time ratio model. The results showed that the Accelerated Failure Time model was better than the Cox Proportional Hazard model because the rate of deterioration and the AIC value was smaller than the other models and related to risk factors, namely the age and status of diabetes mellitus and the length of survival of the patient for 11 days obtained from the estimation of the survival time distribution between the Cox Proportional Hazard model and the Accelerated Failure Time model.
 Keywords: Coronary heart disease, survival analysis, Cox Proportional Hazard, Accelerated Failure Time
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Abidin, Haykal, Novita Eka Chandra, and Mohammad Syaiful Pradana. "Pemodelan Regresi Cox Proportional Hazard Pada Data Perceraian." Unisda Journal of Mathematics and Computer Science (UJMC) 6, no. 2 (2020): 49–58. http://dx.doi.org/10.52166/ujmc.v6i2.2393.
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The purpose of this research is modeling the Cox proportional hazard regression form on divorce data in Pelaihari sub-district, Tanah Laut district, South Kalimantan province. The source of the data comes from the Court Decision in Pelaihari District, Tanah Laut Regency, South Kalimantan. The data analysis technique uses software R with the steps, namely data description, Log-Rank test, checking proportional hazard assumptions, Cox regression model parameter estimation, backward selection with AIC, the best model parameter significance test, calculating Hazard ratio and interpretation of each predictor variable. Based on the results of the analysis and discussion, it was found that for the Log-Rank test, the variable survival time for domestic violence, forced marriage, lying and stories of disgrace differed significantly. While the model that meets the criteria after iteration up to 15 times is the 15th model with the smallest AIC value and p-value <0.05 with factors that significantly influence divorce in Pelaihari sub-district based on modeling results using Cox proportional Hazard regression. are the variables of cheating, gambling, domestic violence, forced marriage, lies, jealousy and disgrace story variables
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Xie, Xianhong, Howard D. Strickler, and Xiaonan Xue. "Additive Hazard Regression Models: An Application to the Natural History of Human Papillomavirus." Computational and Mathematical Methods in Medicine 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/796270.
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There are several statistical methods for time-to-event analysis, among which is the Cox proportional hazards model that is most commonly used. However, when the absolute change in risk, instead of the risk ratio, is of primary interest or when the proportional hazard assumption for the Cox proportional hazards model is violated, an additive hazard regression model may be more appropriate. In this paper, we give an overview of this approach and then apply a semiparametric as well as a nonparametric additive model to a data set from a study of the natural history of human papillomavirus (HPV) in HIV-positive and HIV-negative women. The results from the semiparametric model indicated on average an additional 14 oncogenic HPV infections per 100 woman-years related to CD4 count < 200 relative to HIV-negative women, and those from the nonparametric additive model showed an additional 40 oncogenic HPV infections per 100 women over 5 years of followup, while the estimated hazard ratio in the Cox model was 3.82. Although the Cox model can provide a better understanding of the exposure disease association, the additive model is often more useful for public health planning and intervention.
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Arifitriana, Wirna, and Danardono Danardono. "PENERAPAN MODEL PENYEMBUHAN DENGAN REGRESI COX HAZARD PROPORSIONAL PADA PENYAKIT KANKER KOLOREKTAL." EKSAKTA : Jurnal Penelitian dan Pembelajaran MIPA 4, no. 1 (2019): 66. http://dx.doi.org/10.31604/eksakta.v4i1.66-72.
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Survival analysis is a statistical technique used to analyze the data, aims to determine the variables that affect the outcome of a beginning to end the incident. One model of survival is a cure model is useful for estimating the proportion of patients who recover and the probability of survival of patients who did not recover until the deadline given. Analysis on Cox regression cure model Hazard Proportional with Maximum Likelihood Estimates and Algorithm Expectation Maximization (EM). Keywords: Cox Proportional Hazard Cure Model, MLE, EM algorithm, likelihood ratio test, Wald test.
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Brannath, Werner, Matthias Brückner, Meinhard Kieser, and Geraldine Rauch. "The Average Hazard Ratio – A Good Effect Measure for Time-to-event Endpoints when the Proportional Hazard Assumption is Violated?" Methods of Information in Medicine 57, no. 03 (2018): 089–100. http://dx.doi.org/10.3414/me17-01-0058.
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Summary Background: In many clinical trial applications, the endpoint of interest corresponds to a time-to-event endpoint. In this case, group differences are usually expressed by the hazard ratio. Group differences are commonly assessed by the logrank test, which is optimal under the proportional hazard assumption. However, there are many situations in which this assumption is violated. Especially in applications were a full population and several subgroups or a composite time-to-first-event endpoint and several components are considered, the proportional hazard assumption usually does not simultaneously hold true for all test problems under investigation. As an alternative effect measure, Kalbfleisch and Prentice proposed the so-called ‘average hazard ratio’. The average hazard ratio is based on a flexible weighting function to modify the influence of time and has a meaningful interpretation even in the case of non-proportional hazards. Despite this favorable property, it is hardly ever used in practice, whereas the standard hazard ratio is commonly reported in clinical trials regardless of whether the proportional hazard assumption holds true or not. Objectives: There exist two main approaches to construct corresponding estimators and tests for the average hazard ratio where the first relies on weighted Cox regression and the second on a simple plug-in estimator. The aim of this work is to give a systematic comparison of these two approaches and the standard logrank test for different time-toevent settings with proportional and nonproportional hazards and to illustrate the pros and cons in application. Methods: We conduct a systematic comparative study based on Monte-Carlo simulations and by a real clinical trial example. Results: Our results suggest that the properties of the average hazard ratio depend on the underlying weighting function. The two approaches to construct estimators and related tests show very similar performance for adequately chosen weights. In general, the average hazard ratio defines a more valid effect measure than the standard hazard ratio under non-proportional hazards and the corresponding tests provide a power advantage over the common logrank test. Conclusions: As non-proportional hazards are often met in clinical practice and the average hazard ratio tests often outperform the common logrank test, this approach should be used more routinely in applications.
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Xue, Xiaonan, Xianhong Xie, and Howard D. Strickler. "A censored quantile regression approach for the analysis of time to event data." Statistical Methods in Medical Research 27, no. 3 (2016): 955–65. http://dx.doi.org/10.1177/0962280216648724.
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The commonly used statistical model for studying time to event data, the Cox proportional hazards model, is limited by the assumption of a constant hazard ratio over time (i.e., proportionality), and the fact that it models the hazard rate rather than the survival time directly. The censored quantile regression model, defined on the quantiles of time to event, provides an alternative that is more flexible and interpretable. However, the censored quantile regression model has not been widely adopted in clinical research, due to the complexity involved in interpreting its results properly and consequently the difficulty to appreciate its advantages over the Cox proportional hazards model, as well as the absence of adequate validation procedure. In this paper, we addressed these limitations by (1) using both simulated examples and data from National Wilms’ Tumor clinical trials to illustrate proper interpretation of the censored quantile regression model and the differences and the advantages of the model compared to the Cox proportional hazards model; and (2) developing a validation procedure for the predictive censored quantile regression model. The performance of this procedure was examined using simulation studies. Overall, we recommend the use of censored quantile regression model, which permits a more sensitive analysis of time to event data together with the Cox proportional hazards model.
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Lu, Aiying, Haifeng Li, Yuming Zheng, et al. "Prognostic Significance of Neutrophil to Lymphocyte Ratio, Lymphocyte to Monocyte Ratio, and Platelet to Lymphocyte Ratio in Patients with Nasopharyngeal Carcinoma." BioMed Research International 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/3047802.
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The peripheral blood neutrophil to lymphocyte ratio (NLR), lymphocyte to monocyte ratio (LMR), and platelet to lymphocyte ratio (PLR) have been reported to correlate with the prognosis of many malignancies. This study evaluated the prognostic value of pretreatment NLR, LMR, and PLR in nasopharyngeal carcinoma (NPC). A retrospective analysis of clinical and pathological data of 140 NPC patients without distant metastasis during initial treatment was conducted to identify correlations between NLR, LMR, and PLR and clinicopathological features, overall survival, and progression-free survival. Cox proportional hazard regression analysis was used to reveal the independent factors affecting the prognosis of NPC patients. NLR was associated with T staging, N staging, and overall clinical stage grouping of the NPC patients (P<0.05). NLR ≥ 2.28, LMR < 2.26, and PLR ≥ 174 were significantly associated with a relatively short overall survival (P<0.05). In addition, NLR ≥ 2.28 was significantly associated with a relatively short progression-free survival (P<0.05). Cox proportional hazard regression analysis showed that NLR was an independent prognostic factor in NPC. Pretreatment NLR, LMR, and PLR might be a useful complement to TNM staging in the prognostic assessment of NPC patients.
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Tang, Jessica A., Jeremi M. Leasure, Justin S. Smith, Jenni M. Buckley, Dimitriy Kondrashov, and Christopher P. Ames. "Effect of Severity of Rod Contour on Posterior Rod Failure in the Setting of Lumbar Pedicle Subtraction Osteotomy (PSO)." Neurosurgery 72, no. 2 (2012): 276–83. http://dx.doi.org/10.1227/neu.0b013e31827ba066.
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Abstract BACKGROUND: Rod failure has been reported clinically in pedicle subtraction osteotomy (PSO) to correct flat back deformity. OBJECTIVE: To characterize the fatigue life of posterior screw-rod constructs in the setting of PSO as a function of the severity of rod contour angle. METHODS: A modified ASTM F1717 to 04 was used. Rods were contoured to the appropriate angle for the equivalent 20-, 40-, or 60-degree PSO angles. Testing was performed on a mechanical test frame at 400/40 N and 250/25 N, and specimens were cycled at 4 Hz to failure or run-out at 2 000 000 cycles. The effect of the screw-rod system on fatigue strength of curved rods was compared using Cox proportional hazards regression. RESULTS: At 400 N/40 N, Cox proportional hazards regression indicated that contouring rods from a 20-degree PSO angle to either 40 or 60 degrees significantly decreased fatigue life (hazard ratio = 7863.6, P = .0144). However, contouring rods from a 40-degree PSO angle to 60 degrees had no significant effect on the fatigue life (P &gt; .05). At 250 N/25 N, Cox proportional hazards regression indicated that contouring rods from a 20-degree PSO angle to either 40 or 60 degrees significantly decreased fatigue life (hazard ratio = 7863.6, P = .0144). Furthermore, contouring rods from a 40-degree PSO angle to 60 degrees had a significant effect on the fatigue life (hazard ratio = 7863.6, P = .0144). CONCLUSION: Results suggest that in the setting of PSO, the fatigue life of posterior spinal fixation rods depends largely on the severity of the rod angle used to maintain the vertebral angle created by the PSO and is significantly lowered by rod contouring.
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Nakazone, Marcelo Arruda, Maurício Nassau Machado, Ana Paula Otaviano, Ana Maria Silveira Rodrigues, Augusto Cardinalli-Neto, and Reinaldo Bulgarelli Bestetti. "Prognostic Significance of Chronic Kidney Disease (CKD-EPI Equation) and Anemia in Patients with Chronic Heart Failure Secondary to Chagas Cardiomyopathy." Cardiology Research and Practice 2020 (July 6, 2020): 1–7. http://dx.doi.org/10.1155/2020/6417874.
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Background. Few studies regarding chronic kidney disease (CKD) and anemia have been conducted in patients with Chagas cardiomyopathy (CC). We evaluated the risk prediction performance of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and anemia in CC patients. Methods. From 2000 to 2010, a total of 232 patients were studied in a single-center retrospective study. CKD was defined as creatinine clearance <60 mL/min/1.73 m2 according to CKD-EPI equation. Anemia was defined as hemoglobin <12 g/dL (women) and <13 g/dL (men). Cox proportional hazards models were used to establish predictors for death. Results. At baseline, 98 individuals (42.2%) had criteria for CKD and 41 (17.7%) for anemia. During follow-up, 136 patients (58.6%) died. Independently, CKD and anemia were not associated with all-cause mortality. However, when they coexisted, an additional risk was attributed for these patients. Cox proportional hazard models analysis identified systolic blood pressure (hazard ratio, 0.99; 95% confidence interval (CI), 0.98 to 1.00; P=0.015), implantable cardioverter-defibrillator (hazard ratio, 0.48; 95% CI, 0.27 to 0.85; P=0.012), left anterior fascicular block (hazard ratio, 1.52; 95% CI, 1.08 to 2.13; P=0.017), left ventricular end-diastolic diameter (hazard ratio, 1.04; 95% CI, 1.02 to 1.06; P<0.001), and serum sodium (hazard ratio, 0.95; 95% CI, 0.92 to 0.99; P=0.020) as independent predictors for death. Conclusions. CKD and anemia are not independent predictors for long-term mortality in CC patients. However, the prognosis is poorer in individuals with both comorbidities.
Dissertations / Theses on the topic "Cox Proportional Hazard Ratio"
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Marques, Inês Filipa Costa. "Mortality of elite athletes : an application to football players." Master's thesis, Instituto Superior de Economia e Gestão, 2018. http://hdl.handle.net/10400.5/18092.
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Mestrado em Actuarial Science<br>Os benefícios para a saúde resultantes da prática regular de exercício físico, de uma forma moderada, estão cientificamente comprovados. Contudo, quando se trata de uma abordagem sobre atletas profissionais, os benefícios deixam de ser uma clara evidência, surgindo por vezes sinais de alerta para os seus possíveis efeitos adversos. Para alimentar esta controvérsia, muito têm contribuído os estudos recentes que evidenciam anomalias e doenças cardiovasculares, bem como as frequentes lesões em atletas de elite.
É neste contexto que surge o principal objectivo deste trabalho: investigar se os atletas de elite vivem mais do que a população em geral. Após uma profunda revisão literária inicial relativa à mortalidade dos atletas de elite, procede-se a uma análise de sobrevivência que tem como foco dois grupos de jogadores de futebol profissionais.
Recolheram-se dados relativos à data de nascimento e morte dos jogadores portugueses e espanhóis que representaram a sua selecção, bem como de outras variáveis de interesse para o estudo. Cada grupo de jogadores é comparado com a população geral do respectivo país, usando dados disponíveis na Human Mortality Database, através da estimação de standardised mortality ratios e de curvas de sobrevivência. O years-lost method é também aplicado, fornecendo uma medida de longevidade dos referidos atletas de elite. Ainda é averiguado se a posição dos jogadores e o número de jogos na sua carreira afectam diferencialmente a mortalidade dos mesmos, através dos Cox Proportional Hazard Models. Por fim, as populações dos jogadores portugueses e espanhóis são comparadas entre si.<br>The health benefits of moderate regular physical activity have been clearly demonstrated and are widely consensual. However, there is a growing debate over the potential adverse effects of strenuous physical activity, particularly at a professional level. Recent findings of cardiovascular anomalies in elite athletes coupled with the high frequency of injuries have brought some sports under increased scrutiny.
In this context, the main goal of this work is to investigate whether elite athletes live longer than the general population. After an initial review of the literature on elite athletes' mortality, a comprehensive survival analysis is applied to two populations of professional football players.
Lifespan data and specific occupational variables of Portuguese and Spanish football players, who have represented their national teams in their career, were collected from recognized publicly available sources. Each cohort is then compared to the respective standard population, using available data in the Human Mortality Database, through the estimation of standardised mortality ratios and survival curves. The years-lost method is applied to provide a time dimension measure for these elite athletes' longevity. Furthermore, the association of position on the field and the number of games with overall mortality is accessed using Cox Proportional Hazard Models. At the end, a comparison between the mortality of Portuguese and Spanish football players is carried out.<br>info:eu-repo/semantics/publishedVersion
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Gwaze, Arnold Rumosa. "A cox proportional hazard model for mid-point imputed interval censored data." Thesis, University of Fort Hare, 2011. http://hdl.handle.net/10353/385.
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There has been an increasing interest in survival analysis with interval-censored data, where the event of interest (such as infection with a disease) is not observed exactly but only known to happen between two examination times. However, because so much research has been focused on right-censored data, so many statistical tests and techniques are available for right-censoring methods, hence interval-censoring methods are not as abundant as those for right-censored data. In this study, right-censoring methods are used to fit a proportional hazards model to some interval-censored data. Transformation of the interval-censored observations was done using a method called mid-point imputation, a method which assumes that an event occurs at some midpoint of its recorded interval. Results obtained gave conservative regression estimates but a comparison with the conventional methods showed that the estimates were not significantly different. However, the censoring mechanism and interval lengths should be given serious consideration before deciding on using mid-point imputation on interval-censored data.
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Sandström, Caroline, and Karl Norling. "Female longevity : A survival analysis on 19th century women using the Cox Proportional Hazard model." Thesis, Umeå universitet, Statistiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-49700.
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Pelagia, Ioanna. "Variable selection of fixed effects and frailties for Cox Proportional Hazard frailty models and competing risks frailty models." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/variable-selection-of-fixed-effects-and-frailties-for-cox-proportional-hazard-frailty-models-and-competing-risks-frailty-models(c75c6314-f43e-4d69-a2de-942bece6a404).html.
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This thesis focuses on two fundamental topics, specifically in medical statistics: the modelling of correlated survival datasets and the variable selection of the significant covariates and random effects. In particular, two types of survival data are considered: the classical survival datasets, where subjects are likely to experience only one type of event and the competing risks datasets, where subjects are likely to experience one of several types of event. In Chapter 2, among other topics, we highlight the importance of adding frailty terms on the proposed models in order to account for the association between the survival time and characteristics of subjects/groups. The main novelty of this thesis is to simultaneously select fixed effects and frailty terms through the proposed statistical models for each survival dataset. Chapter 3 covers the analysis of the classical survival dataset through the proposed Cox Proportional Hazard (PH) model. Utilizing a Cox PH frailty model, may increase the dimension of variable components and estimation of the unknown coefficients becomes very challenging. The method proposed for the analysis of classical survival datasets involves simultaneous variable selection on both fixed effects and frailty terms through penalty functions. The benefit of penalty functions is that they identify the non-significant parameters and set them to have a zero effect in the model. Hence, the idea is to 'doubly-penalize' the partial likelihood of the Cox PH frailty model; one penalty for each term. Estimation and selection implemented through Newton-Raphson algorithms, whereas closed iterative forms for the estimation and selection of fixed effects and prediction of frailty terms were obtained. For the selection of frailty terms, penalties imposed on their variances since frailties are random effects. Based on the same idea, we further extend the simultaneous variable selection in the competing risks datasets in Chapter 4, using extended cause-specific frailty models. Two different scenarios are considered for frailty terms; in the first case we consider that frailty terms vary among different types of events (similar to the fixed effects) whereas in the second case we consider shared frailties over all the types of events. Moreover, our 'individual penalization' approach allows for one covariate to be significant for some types of events, in contrast to the frequently used 'group-penalization' where a covariate is entirely removed when it is not significant over all the events. For both proposed methods, simulation studies were conduced and showed that the proposed procedure followed for each analysis works well in simultaneously selecting and estimating significant fixed effects and frailty terms. The proposed methods are also applied to real datasets analysis; Kidney catheter infections, Diabetes Type 2 and Breast Cancer datasets. Association of the survival times and unmeasured characteristics of the subjects was studied as well as a variable selection for fixed effects and frailties implemented successfully.
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Dias, Daniel Alexandre Baptista. "Testes de especificação ao modelo de Hazard proporcional." Master's thesis, Instituto Superior de Economia e Gestão, 2005. http://hdl.handle.net/10400.5/13257.
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Mestrado em Econometria Aplicada e Previsão<br>O estudo dos factores que influenciam o tempo entre dois acontecimentos é um tópico comum a vários ramos das ciências económicas. Na literatura, este tipo de análise é conhecida por "Análise da Duração n e os modelos estatísticos/econométricos que lhe estão associados são os "Modelos de Duroção". No trabalho que se segue iremos apresentar mn conjunto de testes de especificação ao modelo de Hazard Pro porcional assim como iremos analisar as propriedades de amostras finitas de testes de especificação gerais, em particular, testes de momentos condicionais.<br>The analysis of factors inflnencing the time between evento; is a topic common to severa!areas of the economic sciences. ln the literature, this type of ana1ysis is known as Duration Analysis and the inherent econometric models are the Duration Models. ln this work, we will present some specification tests of the Proportional Hazard model and we will also analyse the finite sample properties of general specification tests, in particular, conditional moments tests<br>info:eu-repo/semantics/publishedVersion
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Minya, Kristoffer. "Överlevnadsanalys i tjänsteverksamhet : Tidspåverkan i överklagandeprocessen på Migrationsverket." Thesis, Linköpings universitet, Statistik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-110428.
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Migrationsverket är en myndighet som prövar ansökningar från personer som vill söka skydd, ha medborgarskap, studera eller vill jobba i Sverige. Då det på senare tid varit en stor ökning i dessa ansökningar har tiden för vilket ett beslut tar ökat. Varje typ av ansökning (exempelvis medborgarskap) är en process som består av flera steg. Hur beslutet går igenom dessa steg kallas för flöde. Migrationsverket vill därför öka sin flödeseffektivitet. När beslutet är klart och personen tagit del av det men inte är nöjd kan denne överklaga. Detta är en av de mest komplexa processerna på Migrationsverket. Syftet är analysera hur lång tid denna process tar och vilka steg i processen som påverkar tiden. Ett steg (som senare visar sig ha en stor effekt på tiden) är yttranden. Det är när domstolen begär information om vad personen som överklagar har att säga om varför denne överklagar. För att analysera detta var två metoder relevanta, accelerated failure time (AFT) och \multi-state models (MSM). Den ena kan predicera tid till händelse (AFT) medan den andra kan analysera effekten av tidspåverkan (MSM) i stegen. Yttranden tidigt i processen har stor betydelse för hur snabbt en överklagan får en dom samtidigt som att antal yttranden ökar tiden enormt. Det finns andra faktorer som påverkar tiden men inte i så stor grad som yttranden. Då yttranden tidigt i processen samtidigt som antal yttranden har betydelse kan flödeseffektiviteten ökas med att ta tid på sig att skriva ett informativt yttrande som gör att domstolen inte behöver begära flera yttranden.<br>The Swedish Migration Board is an agency that review applications from individuals who wish to seek shelter, have citizenship, study or want to work in Sweden. In recent time there has been a large increase in applications and the time for which a decision is made has increased. Each type of application (such as citizenship) is a process consisting of several stages. How the decision is going through these steps is called flow. The Swedish Migration Board would therefore like to increase their flow efficiency. When the decision is made and the person has take part of it but is not satisfied, he can appeal. This is one of the most complex processes at the Board. The aim is to analyze how long this process will take and what steps in the process affects the time. One step (which was later found to have a significant effect on time) is opinions. This is when the court requests information on what the person is appealing has to say about why he is appealing. To analyze this, two methods were relevant, accelerated failure time (AFT) and the multi-state models (MSM). One can predict time to event (AFT), the other to analyze the effect of time-manipulation (MSM) in the flow. Opinions early in the process is crucial to how quickly an appeal get judgment while the number of opinions increases the time enormously. There are other factors that affect the time but not so much as opinions. The flow efficiency can be increased by taking time to write an informative opinion which allows the court need not to ask for more opinions.
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Sposito, Ítalo Beltrão. "Continuidade e mudança na política externa dos estados latino-americanos (1945-2008)." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/101/101131/tde-28032016-141512/.
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: Este trabalho tem como objeto o redirecionamento na política externa (RPE) - conceituado como as mudanças mais radicais, abrangentes e rápidas em política externa. Para analisar este fenômeno, são buscadas as principais condições conjunturais que podem aumentar a chance de ocorrência deste evento. Estas condições estão relacionadas ao conceito de Janela Política, que representa o período em que é rompida a inércia política e os tomadores de decisões têm condições de iniciar um processo de RPE. Objetivo: encontrar e delimitar quais as condições conjunturais que aumentam as chances de ocorrência de um RPE. Método: são utilizadas ferramentas metodológicas qualitativas e quantitativas. No segundo capítulo, a análise é feita por meio de um modelo de sobrevivência (Cox Proportional Hazard Model) que analisa o efeito das variáveis sobre os riscos de ocorrência do evento em foco, definido como as alterações mais extremas de comportamento nas votações da Assembleia Geral das Nações Unidas. No terceiro capítulo, é desenvolvida uma análise qualitativa histórica focando especificamente nos casos mais radicais de RPE, buscando identificar padrões comuns no desencadeamento dos processos em estudo; com base nestes casos, são desenvolvidas tipologias explicativas para identificar diferentes caminhos causais que levam ao evento em tela. Resultados: foi identificado que mudanças de regime e de líder político, no âmbito doméstico, e intervenções militares de potências estrangeiras aumentam os riscos de ocorrência de RPE; adicionalmente, a alta polarização política e a mudança de regime, a crise política doméstica com envolvimento de atores internacionais, os processos de isolamento internacional com imposição de sanções econômicas e os períodos de crise econômica com questionamento do modelo econômico vigente por parte dos atores políticos podem combinadamente levar à ocorrência de RPE. Conclusões: apesar da importância do interesses de atores políticos em empreender um projeto de RPE, foi identificado que determinados eventos aumentam os riscos deste processo ocorrer.<br>This thesis object is the foreign policy restructuring (FPR) - conceptualized as the most radical, encompassing, and fast changes in foreign policy. To analyze this phenomenon, there will be sought the main conjuncture conditions that might enhance the chances of this event occurrence. These conditions are related to the Policy Window concept, that represents a period during which the political inertia is disrupted and decision makers have the circumstances to undertake a FPR process. Objective: find and outline the conjectural conditions and variables that increase the chances of occurrence of a FPR. Methods: it will be used qualitative and quantitative methodological tools. In the second chapter, a survival model (Cox Proportional Hazard Model) analyses the effect variables related to the Policy Window concept over the risks of happening a FPR, defined as the most extreme changes of behavior in United Nations General Assembly roll-call votes. In the third chapter, a historical qualitative analysis is undertaken focusing exclusively on the most radical cases of FPR to develop explanatory typologies in order to identify causal conjunctures and common patters that lead to the outcome. Results: we identified that regime and political leader changes, in the national context, and military interventions by foreign powers enhance the risks of FPR occurrence; additionally, high political polarization combined with regime change, political crisis with international forces involvement, processes of international isolation with economic sanctions enforcement, and economic crises with political actors questioning the current economic model might be combined, configuring causal paths to a FPR. Conclusion: despite the importance of main political actors interest in implementing a FPR process, we identified that specific conjunctures and events raise the risks of a positive outcome.
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Belcon, Michael C. "Determinants and Disparities of Survival in Triple-Negative Breast Cancer Patients: A Population-Based Retrospective Longitudinal Cohort Design Utilizing the Cox Proportional Hazard Analytical Model." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2311.
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A significant racial disparity in breast cancer mortality exists among women in the United States. Triple-negative breast cancer (TNBC) is a breast cancer phenotype that may explain, in part, this disparity between white and African American women. The objective of this study was to determine the predictors of survival in TNBC and non-triple-negative breast cancer (NTNBC) patients.
Data on 168,756 female patients with a diagnosis of invasive breast cancer in the Surveillance Epidemiology and End Results (SEER) program were stratified based on breast cancer receptor phenotypes in this retrospective longitudinal cohort study design. Multiple logistic regressions were used for exploring predictors of treatment which showed that not receiving surgery as standard treatment was associated (odds ratio: 95% CI) with TNBC (OR 1.151: 1.042, 1.177), uninsured (OR 3.552: 3.206, 3.937) and African American (OR 1.804: 1.702, 1.912) while not receiving radiation was associated with TNBC (OR 1.151: 1.113, 1.190), uninsured (OR 1.318; 1.217, 1.429). Cox’s hazard models were used, regressing age, race, ethnicity, marital status, health insurance status, histological tumor grade, and treatment status on survival time, the outcome measure.
Analysis revealed that the mean survival time is lower for TNBC [15.60 (± 10.29)] months compared with NTNBC [16.01 (± 10.18)] (p < 0.0001), a difference though small is statistically significant. The independent determinants of survival in TNBC were: young age at diagnosis [(β = 0.033, HR 1.033 (1.026, 1.041)]; being African American [(β = 0.182, HR 1.200 (1.117, 1.289)], being married [(β = - 0.362, HR 0.697 (0.658, 0.737)]; higher tumor histological grades [β = 1.034, HR 2.812 (2.159,3.661)]; uninsured [(β = 0.541, HR 1.717 (1.481, 1.992)]; no surgery [(β = 2.156, HR 8.633 (8.152, 9.143)], or no radiation treatment [(β = 0.489, HR 1.630 (1.535,1.73)].
African American race, uninsured status, higher grade at diagnosis, inadequate treatment are independent predictors of poor survival among breast cancer patients; importantly, TNBC had a lower survival than that of NTNBC patients. A higher proportion of TNBC patients had a diagnosis at younger age, with higher tumor grade and was of the African American race. The survival disparity in African American patients may be partially explained by disproportionately higher TNBC cases among them, as well as, rates of not receiving standard treatments.
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Nichols, Bradley C. "Foraging Ecology of Mountain Lions in the Sierra National Forest, California." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/6262.
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Studies of predator-prey and predator-predator interactions are needed to provide information for decision-making processes in land management agencies. Mountain lions (Puma concolor) are opportunistic carnivores that prey on a wide variety of species. In the Sierra National Forest, CA, they have not been studied since 1987 and their current interactions with their prey and other predators are unknown. Forest managers in this region are concerned with declines of fishers (Pekania pennanti) and studies have shown intraguild predation to be a leading cause of fisher mortality in this area. Managers are interested in learning more about mountain lion predation patterns with regard to prey preference, but also how lions traverse and use the landscape and how anthropogenic activities may be increasing lion predation risk on fishers.
Using GPS radio-collar technology, we examined mountain lion kill rates and prey composition at 250 kill sites. We found mule deer (Odocoileus hemionus) to be their main source of prey (81%) with gray foxes (Urocyon cinereoargenteus) comprising 13.2% of prey composition. We did not detect any fisher predation during our 2-year study; however, during our study, the Kings River Fisher Project experienced extremely low juvenile fisher survival.
To gain a better understanding of seasonal resource selection by mountain lions, we developed resource selection functions (RSF) while they were moving through the landscape and when killing prey. We developed RSF models for all data across the study area, as well as, for a subset of data encompassing an area where LiDAR (Light Detection and Ranging) data had been collected. Within the LiDAR study area, we digitized unmapped roads and skid trails using a Bare Earth data set. We found mountain lion ‘moving’ locations showed selection for close proximity to streams during summer months and selection for ruggedness and steeper slopes during both summer and winter. With 3 of the 4 RSF models at kill sites showing high risk of predation within close proximity to either digitized roads/skid trails or mapped roads, we recommend managers map all anthropogenically created linear landscape features and consider restoring these linear features to pre-treatment landscape conditions following timber harvest.
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Lindberg, Erik. "A study of the effect of inbreeding in Skellefteå during the 19th century : Using Cox Proportional hazard model to analyze lifespans and Poisson/Negative Binomial regression to analyze fertility." Thesis, Umeå universitet, Statistik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-122687.
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Inbreeding is defined as when two individuals who are related mate and produce offspring. The level of inbreeding for an individual can be determined by calculating an inbreeding coefficient. Inbreeding can enhance both positive and negative traits. The risk for recessive diseases also increase. Data from old church records from the region of Skellefteå covering individuals from the late 17th century to the early 20th century has been made available. From this data parent-child relations can be observed and levels of inbreeding calculated. By analyzing the available data using Cox Proportional Hazard regression model it was shown that the level inbreeding affected the lifespan of an individual negatively if the parents are second cousins or more closely related. Using Poisson- and Negative Binomial regression, no evicence of an effect of inbreeding of fertility could be found.
Books on the topic "Cox Proportional Hazard Ratio"
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Golub, Jonathan. Survival Analysis. Edited by Janet M. Box-Steffensmeier, Henry E. Brady, and David Collier. Oxford University Press, 2009. http://dx.doi.org/10.1093/oxfordhb/9780199286546.003.0023.
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This article provides a discussion of survival analysis that presents another way to incorporate temporal information into analysis in ways that give advantages similar to those from using time series. It describes the main choices researchers face when conducting survival analysis and offers a set of methodological steps that should become standard practice. After introducing the basic terminology, it shows that there is little to lose and much to gain by employing Cox models instead of parametric models. Cox models are superior to parametric models in three main respects: they provide more reliable treatment of the baseline hazard and superior handling of the proportional hazards assumption, and they are the best for handling tied data. Moreover, the illusory benefits of parametric models are presented. The greater use of Cox models enables researchers to elicit more useful information from their data, and allows for more reliable substantive inferences about important political processes.
Book chapters on the topic "Cox Proportional Hazard Ratio"
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Abu Hasan, Nurhasniza Idham, Nor Azura Md. Ghani, Norazan Mohamed Ramli, Khairul Asri Mohd Ghani, and Khairul Izan Mohd Ghani. "Prognostic Factors for Rheumatics Heart Disease After Mitral Valve Repair Surgery Using Cox Proportional Hazard Model." In Regional Conference on Science, Technology and Social Sciences (RCSTSS 2016). Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0074-5_66.
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"The Cox Proportional Hazard Regression Model and Advances." In Survival Analysis. John Wiley & Sons, Ltd, 2012. http://dx.doi.org/10.1002/9781118307656.ch5.
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Jung, Chau-Ren, Yu-Ting Lin, and Bing-Fang Hwang. "Ozone, Particulate Matter, and Newly Diagnosed Alzheimer’s Disease: A Population-Based Cohort Study in Taiwan." In Advances in Alzheimer’s Disease. IOS Press, 2021. http://dx.doi.org/10.3233/aiad210002.
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Several studies with animal research associate air pollution in Alzheimer’s disease (AD) neuropathology, but the actual impact of air pollution on the risk of AD is unknown. Here, this study investigates the association between long-term exposure to ozone (O3) and particulate matter (PM) with an aerodynamic diameter equal to or less than 2.5 μm (PM2.5), and newly diagnosed AD in Taiwan. We conducted a cohort study of 95,690 individuals’ age ≥ 65 during 2001–2010. We obtained PM10 and O3 data from Taiwan Environmental Protection Agency during 2000–2010. Since PM2.5 data is only accessible entirely after 2006, we used the mean ratio between PM2.5 and PM10 during 2006–2010 (0.57) to estimate the PM2.5 concentrations from 2000 to 2005. A Cox proportional hazards model was used to evaluate the associations between O3 and PM2.5 at baseline and changes of O3 and PM2.5 during the follow-up period and AD. The adjusted HR for AD was weakly associated with a raised concentration in O3 at baseline per increase of 9.63 ppb (adjusted HR 1.06, 95% confidence interval (CI) 1.00–1.12). Further, we estimated a 211% risk of increase of AD per increase of 10.91 ppb in O3 over the follow-up period (95% CI 2.92–3.33). We found a 138% risk of increase of AD per increase of 4.34 μg/m3 in PM2.5 over the follow-up period (95% CI 2.21–2.56). These findings suggest long-term exposure to O3 and PM2.5 above the current US EPA standards are associated with increased the risk of AD.
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Beaudry, Catherine, and Joël Levasseur. "Collaboration, Innovation, and Funding as Survival Factors for Canadian Biotechnology SMEs." In Biotechnology. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-8903-7.ch062.
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This chapter aims to determine the factors, such as collaboration, research and development, intellectual property, product management and financing, that influence the survival of biotechnology firms in Canada. The research uses data from four biannual surveys on the use and development of biotechnology collected by Statistics Canada between 1999 and 2005, and follows these firms in the official business register of the organisation up to 2009, to build a Cox proportional hazard model of firm survival. The research finds that firms that collaborate for exploration purposes have better chances of survival than others. Results also suggest that a larger number of patents decreases the probability of survival. Investigation of the product development process shows that because of the vast resources necessary for clinical research, firms enter the production and commercialisation stage in a weak position, which may then result in firm exit.
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Beaudry, Catherine, and Joël Levasseur. "Collaboration, Innovation, and Funding as Survival Factors for Canadian Biotechnology SMEs." In Comparative Approaches to Biotechnology Development and Use in Developed and Emerging Nations. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1040-6.ch013.
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This chapter aims to determine the factors, such as collaboration, research and development, intellectual property, product management and financing, that influence the survival of biotechnology firms in Canada. The research uses data from four biannual surveys on the use and development of biotechnology collected by Statistics Canada between 1999 and 2005, and follows these firms in the official business register of the organisation up to 2009, to build a Cox proportional hazard model of firm survival. The research finds that firms that collaborate for exploration purposes have better chances of survival than others. Results also suggest that a larger number of patents decreases the probability of survival. Investigation of the product development process shows that because of the vast resources necessary for clinical research, firms enter the production and commercialisation stage in a weak position, which may then result in firm exit.
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"Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists." In Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists, edited by Chaunte Lewis, John M. Farrell, Kelly L. Sams, Emily R. Cornwell, and Rodman G. Getchell. American Fisheries Society, 2017. http://dx.doi.org/10.47886/9781934874462.ch15.
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<em>Abstract</em>.—Viral hemorrhagic septicemia virus (VHSV) has been found in fish populations throughout the Great Lakes basin since 2003. It is a single-stranded RNA virus that affects a number of fish species, including Muskellunge <em>Esox masquinongy</em>, a major predator in these waters. The purpose of this experiment was to compare the virulence of four strains of VHSV IVb (MI03, vcG002, FPL2013-002, and FPL2014-001). Age-0 Muskellunge were randomly assigned to one of the strains and exposed to either a high (5 × 10<sup>5</sup> plaque forming units/mL) or low (5 × 104 plaque forming units/mL) dose for 1 h by immersion. Fish were then monitored for clinical signs of infection, such as petechial hemorrhages, lethargy, and death, whereupon brain and pooled organ samples were harvested using aseptic technique. Quantitative reverse transcription polymerase chain reaction assays in Muskellunge were performed along with viral isolation in order to confirm the presence of VHSV. Results of the Cox proportional hazard regression models did demonstrate a difference when comparing the time to death of the high dose versus the low dose, but no difference was observed when comparing the time to death of the four isolates over the course of the experiment. When comparing viral load in Muskellunge pooled spleen, heart, liver, and anterior and posterior kidneys or separate brain samples, there were no differences between the strains or the doses detected. Future studies with lower doses closer to the LD50 may differentiate changes in virulence properties of VHSV IVb.
Conference papers on the topic "Cox Proportional Hazard Ratio"
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Aliberti, Márlon Juliano Romero, Claudia Szlejf, Claudia Kimie Suemoto, Murilo Bacchini Dias, Wilson Jacob-Filho, and Thiago Junqueira Avelino-Silva. "FRAILTY AND MORTALITY RISK IN PATIENTS WITH SEVERE COVID-19: PROGNOSIS BEYOND THE AGE CRITERION." In XXII Congresso Brasileiro de Geriatria e Gerontologia. Zeppelini Publishers, 2021. http://dx.doi.org/10.5327/z2447-21232021res05.
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OBJECTIVE: To investigate the association between frailty and death in hospitalized patients with COVID-19. METHODOLOGY: Prospective cohort study with patients ≥ 50 years hospitalized with COVID-19. Frailty was assessed using the Clinical Frailty Scale and the frailty index. Patients with a Clinical Frailty Scale score ≥ 5 were considered frail. The primary endpoints were mortality at 30 and 100 days after hospital admission. We used Cox proportional hazard models to investigate the association between frailty and mortality. We also explored whether frailty predicted different mortality levels among patients within strata of similar age and acute disease severity (Sequential Organ Failure Assessment score). RESULTS: A total of 1,830 patients were included (mean age 66 years; 58% men; 27% frail according to Clinical Frailty Scale score). The mortality risk at 30 days (adjusted hazard ratio = 1.7; 95% CI 1.4 - 2.1; p <0.001) and 100 days (adjusted hazard ratio = 1.7; 95% CI 1.4 - 2.1; p <0.001) was almost double for frail patients. The Clinical Frailty Scale also predicted different mortality levels among patients within strata of similar age and acute disease severity. Frailty intensified the effect of acute disease severity on the risk of death (p for interaction = 0.01). Of note, the Clinical Frailty Scale achieved outstanding accuracy to identify frailty according to the frailty index (area under the ROC curve = 0.94; 95% CI 0.93 - 0.95). CONCLUSIONS: Our results encourage the use of the Clinical Frailty Scale in association with measures of acute disease severity to determine prognosis and promote adequate resource allocation in hospitalized patients with COVID-19.
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Garcez, Flávia Barreto, Wilson Jacob-Filho, and Thiago Junqueira Avelino-Silva. "EFFECT OF AMBIENT TEMPERATURE ON MORTALITY IN ACUTELY ILL HOSPITALIZED OLDER PATIENTS." In XXII Congresso Brasileiro de Geriatria e Gerontologia. Zeppelini Publishers, 2021. http://dx.doi.org/10.5327/z2447-21232021res03.
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OBJECTIVE: To investigate the association between extremes of temperature and increased hospital mortality in acutely ill older patients. METHODS: A prospective cohort study of acutely ill patients aged 60 years or older, admitted to the geriatric ward of Hospital das Clinicas at the University of Sao Paulo Medical School, from 2009 to 2015. Meteorological data were obtained through the System of Information on Air Quality of the state of Sao Paulo. The average daily temperatures were categorized according to percentiles (p). Temperatures at p95 and p90 were defined as extreme heat and those below p10 and p5 as extreme cold. We collected sociodemographic, clinical, functional, and laboratory data on admission using a standardized comprehensive geriatric assessment. The primary outcome was hospital mortality. We performed multivariate analyses using Cox proportional hazards model adjusted for confounders. RESULTS: We included 1403 patients, with a mean age of 80 years; 61% were women. The overall mortality was 19%. Temperature cutoffs by percentile were 15, 16, 25, and 26°C. The adjusted hazard ratio for all-cause mortality in the ≥ 26°C temperature group compared to the 16.1–25.0°C group was 1.89 (27 vs 18%; 95%CI 1.14–3.12; p = 0.013). There was no significant association between the other temperature groups and mortality. CONCLUSIONS: A daily temperature > 26°C was independently associated with increased hospital mortality. Health administrators and clinicians should be aware of the potential negative effects of high ambient temperatures on hospitalized older patients.
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"FAILURE PREDICTION USING THE COX PROPORTIONAL HAZARD MODEL." In 6th International Conference on Software and Data Technologies. SciTePress - Science and and Technology Publications, 2011. http://dx.doi.org/10.5220/0003557802010206.
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Shen, Yu, Yong Yang, Bin Ji, Zeyang Tang, Fan Yang, and Lei Wan. "Influence Factors Analysis of Distribution Transformer Fault Using Cox Proportional Hazard Model." In 2019 International Conference on Intelligent Computing, Automation and Systems (ICICAS). IEEE, 2019. http://dx.doi.org/10.1109/icicas48597.2019.00091.
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Grzyb, Megan, Amber Zhang, Cristina Good, et al. "Multi-task cox proportional hazard model for predicting risk of unplanned hospital readmission." In 2017 Systems and Information Engineering Design Symposium (SIEDS). IEEE, 2017. http://dx.doi.org/10.1109/sieds.2017.7937729.
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Deng, Xiao-Lan, and Ting Wang. "Stock Market Factors and Risk of Financial Distress: An Empirical Analysis Using Cox proportional Hazard Model." In 2008 4th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM). IEEE, 2008. http://dx.doi.org/10.1109/wicom.2008.2420.
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Arora, Sanvi, Aman Kumar, and Saurabh Sambhav. "Analysing the Effect of Gender on Mortality of COVID-19 Patients through Cox-Proportional Hazard Model." In 2021 International Conference on Intelligent Technologies (CONIT). IEEE, 2021. http://dx.doi.org/10.1109/conit51480.2021.9498331.
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Alsaedi, Abdalrahman, Ikhlas Abdel-Qader, Niaz Mohammad, and Alvis C. Fong. "Extended cox proportional hazard model to analyze and predict conversion from mild cognitive impairment to alzheimer's disease." In 2018 IEEE 8th Annual Computing and Communication Workshop and Conference (CCWC). IEEE, 2018. http://dx.doi.org/10.1109/ccwc.2018.8301669.
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Riyadina, Woro, Dewi Kristanti, Julianty Pradono, Ekowati Rahajeng, and Yuda Turana. "A Cohort Study on The Primary Prevention of Stroke Incidence in Adult Population in Bogor, West Java." In The 7th International Conference on Public Health 2020. Masters Program in Public Health, Universitas Sebelas Maret, 2020. http://dx.doi.org/10.26911/the7thicph.01.25.
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ABSTRACT Background: Incidence of stroke showed an increasing trend in Indonesia, 12 new cases per 1,000 in 2013, and 19 new cases per 1,000 in 2018 despite the stroke control programs from the government. This study aimed to estimate Cumulative Incidence, Incidence Rate, and Population Attributable Fraction (PAF). This study also estimated the effect of blood pressure, physical activity, blood sugar levels, and smoking habits on the risk of stroke in adults. Subjects and Method: This was a cohort study conducted for 6 years in 5 Districts, Bogor City, West Java. An adult population of 5,189 subjects with aged ≥25 years was selected. The dependent variable was stroke. The independent variables included blood pressure, physical activity, blood sugar level, and smoking habits. Data for independent variables (except blood sugar level) were collected by using questioners. Data were analyzed by Cox Proportional Hazard Model. Results: The Cumulative Incidence was 2.09% and Incidence Rate was 480 new stroke cases per 100,000 person-year (CI 95%= 130 to 670) over 6 years. Predictors of stroke incidence were hypertension (HR= 2.50; CI 95%= 1.50 to 4.10; p= 0.001), low physical activity (HR= 2.40; CI 95%= 1.50 to 3.90; p< 0.001), high blood sugar level (HR= 3; CI 95%= 1.70 to 5.50; p= 0.001), and heavy smoking (HR= 3.90; CI 95%= 1.40 to 11.10; p= 0.007). PAF of blood sugar level and physical activity was 67.75%, and able to reduce stroke incidence by 1,990 from 2,937. Conclusion: Hypertension, low physical activity, high blood sugar level, and heavy smoking are predictors of stroke in adult. Primary prevention by increasing physical activity and decreasing blood sugar level can reduce incidence of stroke. Keywords: stroke, Cumulative Incidence, Incidence Rate, PAF, primary prevention Correspondence: Woro Riyadina. National Institute of Health Research and Development, Ministry of Health, Indonesia. Email: w.riyadina02@gmail.com. Mobile: +6281297673074. DOI: https://doi.org/10.26911/the7thicph.01.25
Reports on the topic "Cox Proportional Hazard Ratio"
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Mirel, Lisa. NHSR 155: Comparative Analysis of the National Health and Nutrition Examination Survey Public-Use and Restricted-Use Linked Mortality Files - Production Schedule. National Center for Health Statistics (U.S.), 2021. http://dx.doi.org/10.15620/cdc:104774.
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This report describes a comparative analysis of the public-use and restricted-use NHANES LMFs. Cox proportional hazards models were used to estimate relative hazard ratios for a standard set of sociodemographic covariates for all-cause as well as cause-specific mortality, using the public-use and restricted-use NHANES LMFs.
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Mirel, Lisa, Cindy Zhang, Christine Cox, Ye Yeats, Félix Suad El Burai, and Golden Cordell. Comparative analysis of the National Health and Nutrition Examination Survey public-use and restricted-use linked mortality files. Centers for Disease Control and Prevention (U.S.), 2021. http://dx.doi.org/10.15620/cdc:104744.
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"Objectives—Linking national survey data with administrative data sources enables researchers to conduct analyses that would not be possible with each data source alone. Recently, the Data Linkage Program at the National Center for Health Statistics (NCHS) released updated Linked Mortality Files, including the National Health and Nutrition Examination Survey data linked to the National Death Index mortality files. Two versions of the files were released: restricted-use files available through NCHS and Federal Statistical Research Data Centers and public-use files. To reduce the reidentification risk, statistical disclosure limitation methods were applied to the public-use files before they were released. This included limiting the amount of mortality information available and perturbing cause of death and follow-up time for select records. Methods—To assess the comparability of the restricted-use and public-use files, relative hazard ratios for all-cause and cause-specific mortality using Cox proportional hazards models were estimated and compared. Results—The comparative analysis found that the two data files yield similar descriptive and model results. Suggested citation: Mirel LB, Zhang C, Cox CS, Ye Y, El Burai Félix S, Golden C. Comparative analysis of the National Health and Nutrition Examination Survey public-use and restricted-use linked mortality files. National Health Statistics Reports; no 155. Hyattsville, MD: National Center for Health Statistics. 2021. DOI: https://doi.org/10.15620/cdc:104744. CS323656 nhsr155-508.pdf"