Dissertations / Theses on the topic 'Adverse outcome assessment'

This thesis comprises a rigorous and coherent body of work related to the use of the HCR-20 and the START to inform risk assessment and management of secure mental health inpatients. The thesis contributes significant theoretical and applied knowledge by: 1) investigating the extent to which these tools can be generalised beyond restricted validation samples to the full range of individuals in contact with secure services, 2) determining whether they can aid assessment and management of adverse outcomes beyond aggression, and 3) offering practical, empirically-derived advice for clinicians regarding management strategies that may reduce the occurrence of adverse events. This collection of papers has used considerably novel methods, such as rocreg analysis in risk assessment of behavioural outcomes, and high quality, routinely collected data to gain a more realistic representation of what occurs in clinical practice. Further, the papers draw on larger sample sizes than have previously been reported in this area, allowing for more complex statistical analysis. This thesis has helped clarify the contexts in which these instruments perform effectively and therefore has important implications for clinical risk assessment in inpatient settings. Specifically, there is evidence that the HCR-20 and the START may aid assessment and management of aggression for the majority of groups examined, and that both tools have some efficacy for predicting self-harm among female populations. However, the HCR-20 should not be used to inform prediction and management of aggression and self-harm for individuals with developmental and organic disorders and is unlikely to be beneficial at informing risk management strategies targeting self-harm among males; the START should not be used to inform prediction and management of substance abuse, victimisation, or unauthorised leave. Finally, this thesis highlights a number of directions for future research to continue advancement in this area.

Studies investigating exposure to disinfection by-products (DBPs) via chlorinated waters during pregnancy and adverse fetal growth outcomes have been limited by potential exposure measurement error, lack of exposure assessment validation and potential residual confounding. Factors driving DBP exposure are poorly understood, making it difficult to target resources appropriately in order to improve exposure assessment. These issues were investigated through DBP exposure assessment and validation for a new investigation of DBPs and fetal growth within the Born in Bradford (BiB) cohort study. Analysis of individual water use in the BiB cohort found that water consumption, showering, bathing and swimming varied by demographic and lifestyle factors. Sampling, analysis, and modelling of trihalomethanes (THMs) in tap water showed that THM concentrations exhibited clear seasonal variation, but spatial variability was limited across the study area. Various metrics of exposure to THMs during pregnancy were created, including ‘personalised’ semi-individual metrics. Analysis of these metrics revealed individual water use to be the main driver of THM exposure in this cohort, with spatial and temporal variability having little influence. Compared with a fully integrated THM exposure metric (incorporating ingestion, showering/bathing and swimming), metrics based only on THM concentrations or THM ingestion misclassified over 50% of women. A nested validation study was conducted using a 7-day water diary and urinary trichloroacetic acid (TCAA) biomarker. This found error in self-reported water use and TCAA ingestion estimates to vary by employment status - error being greater for employed women. Urinary TCAA was not correlated with TCAA in tap water, reinforcing that individual water use is the most influential driver of DBP exposure in this cohort. Recommendations for future research include improved individual water use assessment covering more activities and time-points in pregnancy, stratified analysis of questionnaire validation studies, and use of urinary TCAA as a main exposure measure in epidemiological studies.

Disinfection by-products (DBPs) are a major group of water contaminants and their role in causing adverse health outcomes, including adverse pregnancy outcomes, endocrine disruption, respiratory related adverse health outcomes and cancer has been subject to extensive epidemiological and toxicological research and review. Determination of safe exposure to DBPs, particularly within drinking water supplies, has been a topic of extensive debate, with a wide range of acceptable levels set across the industrialized world. The focus of the research in this thesis was on two of the main health outcomes associated with DBP exposure, namely adverse pregnancy outcomes and asthma related symptoms. To assess adverse pregnancy outcomes in Perth, an extensive classification quantification of the major DBPs in Perth drinking water was conducted. A registrybased prevalence study was carried out to assess birth defects in relation to high, medium and low DBP areas (defined by the water sampling and analysis). It was found that women living in high THM areas are 22% (odds ratio (OR) 1.22, 95% confidence interval (95% CI) 1.01-1.48) more likely of having a baby with any birth defect. High exposure was also strongly associated with an increased risk of having a baby with a cardiovascular defect (62% increased risk). Low birth weight and prematurity were also assessed; however these outcomes were not associated with an increased risk through an increase in exposure. Following on from this analysis, a population risk assessment model was developed for DBPs in high exposure environments. This involved a three step process: (i) Firstly a questionnaire-based validation and reliability study was used to assess water consumption patterns of a population of pregnant women in Perth. (ii) Secondly a prediction model for teratogenic burden of DBPs in Perth was developed, related to the exposure patterns of the population of pregnant women involved in the validation and reliability study. (iii) Finally, combining the information collected in (i) and (ii), along with the regression slope estimates for birth weight from the prevalence study (defined in Section 2.2.1), a dose-response model for THMs and birth weight was developed. Predictive simulations for birth weights at given THM levels were then conducted. It was estimated that pregnant women in Perth are exposed to between 0.3 – 4.10 µg/day ingested TTHM, and of this, the more toxic brominated forms accounted for between 0.27 – 3.69 µg/day. Based on a dose-response model used, birthweights calculated for the ‘hypothetical’ exposures ranged from 3403.2g for the highest exposure to 3503.5g in the lowest exposure, which is a difference of over 100g. Although the resulting reduction in birth weight is not extreme, there is still a significant reduction in birth weight present as exposure to TTHMs increases. This is the first doseresponse model to be developed to assess an adverse pregnancy outcome based on pregnant women exposure data, and will be a useful tool for assessing varying exposures throughout not only Australia but also throughout the industrialised world, where DBP exposure is highly prevalent.

Background: Venous thromboembolism (VTE), comprising the conditions of deep vein thrombosis (DVT) and pulmonary embolism (PE), is a common acute cardiovascular event associated with increased long-term morbidity, functional disability, all-cause mortality, and high rates of recurrence. Major advances in identification, prophylaxis, and treatment over the past 3-decades have likely changed its clinical epidemiology. However, there are little published data describing contemporary, population-based, trends in VTE prevention and management. Objectives: To examine recent trends in the epidemiology of clinically recognized VTE and assess the risk of recurrence after a first acute episode of VTE. Methods: We used population-based surveillance to monitor trends in acute VTE among residents of the Worcester, Massachusetts, metropolitan statistical area (WMSA) from 1985 through 2009, including in-hospital and ambulatory settings. Results: Among 5,025 WMSA residents diagnosed with acute PE and/or lower-extremity DVT between 1985 and 2009 (mean age = 65 years), 46% were men and 95% were white. Age- and sex-adjusted annual event rates (per 100, 000) of clinically recognized acute first-time and recurrent VTE was 142 overall, increasing from 112 in 1985/86 to 168 in 2009, due primarily to increases in PE occurrence. During this period, non-invasive diagnostic VTE testing increased, vi while treatment shifted from the in-hospital (chiefly with warfarin and unfractionated heparin) to out-patient setting (chiefly with low-molecular-weight heparins and newer anticoagulants). Among those with community-presenting first-time VTE, subsequent 3-year cumulative event rates of key outcomes decreased from 1999 to 2009, including all-cause mortality (41% to 26%), major bleeding episodes (12% to 6%), and recurrent VTE (17% to 9%). Active-cancer (with or without chemotherapy), a hypercoagulable state, varicose vein stripping, and Inferior vena cava filter placement were independent predictors of recurrence during short- (3-month) and long-term (3-year) follow-up after a first acute episode of VTE. We developed risk score calculators for VTE recurrence based on a 3-month prognostic model for all patients and separately for patients without active cancer. Conclusions: Despite advances in identification, prophylaxis, and treatment between 1985 and 2009, the disease burden from VTE in residents of central Massachusetts remains high, with increasing annual events. Declines in the frequency of major adverse outcomes between 1999 and 2009 were reassuring. Still, mortality, major bleeding, and recurrence rates remained high, suggesting opportunities for improved prevention and treatment. Clinicians may be able to use the identified predictors of recurrence and risk score calculators to estimate the risk of VTE recurrence and tailor outpatient treatments to individual patients.

Background: Venous thromboembolism (VTE), comprising the conditions of deep vein thrombosis (DVT) and pulmonary embolism (PE), is a common acute cardiovascular event associated with increased long-term morbidity, functional disability, all-cause mortality, and high rates of recurrence. Major advances in identification, prophylaxis, and treatment over the past 3-decades have likely changed its clinical epidemiology. However, there are little published data describing contemporary, population-based, trends in VTE prevention and management. Objectives: To examine recent trends in the epidemiology of clinically recognized VTE and assess the risk of recurrence after a first acute episode of VTE. Methods: We used population-based surveillance to monitor trends in acute VTE among residents of the Worcester, Massachusetts, metropolitan statistical area (WMSA) from 1985 through 2009, including in-hospital and ambulatory settings. Results: Among 5,025 WMSA residents diagnosed with acute PE and/or lower-extremity DVT between 1985 and 2009 (mean age = 65 years), 46% were men and 95% were white. Age- and sex-adjusted annual event rates (per 100, 000) of clinically recognized acute first-time and recurrent VTE was 142 overall, increasing from 112 in 1985/86 to 168 in 2009, due primarily to increases in PE occurrence. During this period, non-invasive diagnostic VTE testing increased, vi while treatment shifted from the in-hospital (chiefly with warfarin and unfractionated heparin) to out-patient setting (chiefly with low-molecular-weight heparins and newer anticoagulants). Among those with community-presenting first-time VTE, subsequent 3-year cumulative event rates of key outcomes decreased from 1999 to 2009, including all-cause mortality (41% to 26%), major bleeding episodes (12% to 6%), and recurrent VTE (17% to 9%). Active-cancer (with or without chemotherapy), a hypercoagulable state, varicose vein stripping, and Inferior vena cava filter placement were independent predictors of recurrence during short- (3-month) and long-term (3-year) follow-up after a first acute episode of VTE. We developed risk score calculators for VTE recurrence based on a 3-month prognostic model for all patients and separately for patients without active cancer. Conclusions: Despite advances in identification, prophylaxis, and treatment between 1985 and 2009, the disease burden from VTE in residents of central Massachusetts remains high, with increasing annual events. Declines in the frequency of major adverse outcomes between 1999 and 2009 were reassuring. Still, mortality, major bleeding, and recurrence rates remained high, suggesting opportunities for improved prevention and treatment. Clinicians may be able to use the identified predictors of recurrence and risk score calculators to estimate the risk of VTE recurrence and tailor outpatient treatments to individual patients.

Qin, Yun.<br>"April 2002."<br>Thesis (Ph.D.)--Chinese University of Hong Kong, 2002.<br>Includes bibliographical references (p. 229-254).<br>Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.<br>Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.<br>Mode of access: World Wide Web.<br>Abstracts in English and Chinese.

Faculty of health sciences School of Public Health 0204521g dgresie@yahoo.co.uk;dgresie@hotmail.com<br>Ethylene oxide is used widely in hospitals as a gaseous sterilant for heat-sensitive medical items, surgical instruments and other objects and fluids that come into contact with biological tissues. Although ethylene oxide is recognised as a reproductive toxicant in humans, so far few studies have been carried out to investigate the association between exposure to ethylene oxide and the occurrence of adverse reproductive outcomes (Hemminki et al 1982 and 1983; Rowland et al, 1996; Yakubova et al, 1976). The results of these studies suggested that ethylene oxide is capable of causing reproductive dysfunction and that further research is needed in order to understand its effects on reproductive health. This study investigated the association between exposure to ethylene oxide during pregnancy and adverse reproductive outcome in women sterilising staff working in sterilising units using ethylene oxide in Gauteng province, South Africa. The study had the following objectives: 1) to describe the extent and nature of ethylene oxide use in sterilising units operational in medical facilities in Gauteng; 2) to assess the current exposure to ethylene oxide in sterilising units in Gauteng; 3) to collect information on the last recognised pregnancy using a questionnaire; 4) to assess the validity of the information on the evolution and outcome of the last recognised pregnancy collected by the means of the questionnaire; 5) to assess the association between occupational exposure to ethylene oxide during pregnancy and adverse reproductive outcome. The study population was represented by singleton pregnancies that: 1) occurred in women currently working in sterilising units using ethylene oxide in Gauteng province, South Africa; 2) were the last recognised pregnancy occurring in these women after the 1st January 1992; 3) occurred while the mother was employed. The adverse reproductive outcome was defined as the occurrence of any the following: spontaneous abortion, still birth, pregnancy loss (spontaneous abortion or still birth), low birth weight and combined adverse reproductive outcome (spontaneous abortion, still birth or low birth weight). The study enrolled 68.8% of the medical facilities in Gauteng that were using ethylene oxide to sterilise medical equipment. The majority of the employees working in the sterilising units included in the study were women (96.6%) and they were employed in one of the following jobs: technician (operator), instrument packer and cleaner. xiii Most of the sterilising units participating in the study used ethylene oxide sterilisation daily and only 15.4% of them reported that the employees operating the ethylene oxide steriliser used protective clothing. Recorded levels of ethylene oxide were provided by 46.2% of the sterilising units; they were all bellow 0.25 ppm (the South African long-term exposure limit for occupational exposure to ethylene oxide is 5 ppm). Changes in ethylene oxide sterilisation equipment and or technology were reported by 42.3% of the sterilising units and they were all engineering control measures aimed at reducing exposure to ethylene oxide. Measurements of the current levels of ethylene oxide were performed at the time of the study by the National Institute for Occupational Health using hydrobromic acid-coated petroleum charcoal tubes connected to calibrated Gilian pumps through which air containing ethylene oxide was drawn. The samples were analysed by the Analytical Services of the National Institute for Occupational Health. A total of 418 samples were collected (100 blank samples, 97 personal samples and 221 static samples). Quality control was ensured by the following methods: 1) verification by an Approved Inspection Authority; 2) collection of duplicate samples; 3) collection of blank samples. These measurements showed that exposure to ethylene oxide still occurred in sterilising units (ethylene oxide was detected in 9 out of the 10 public hospitals) and that the employees most exposed are the ones working with the ethylene oxide steriliser (technician or operator). There were 113 women working in the sterilising units enrolled in the study who had been pregnant after the 1st January 1992; 109 of them agreed to participate in the study and to complete the questionnaire. Information on exposure to ethylene oxide during pregnancy was obtained from three sources: walk-through survey, questionnaire-collected data and measurements of the levels of ethylene oxide in sterilising units at the time of the study. Information on the evolution and outcome of these pregnancies was gathered from the mother using a questionnaire. The questionnaire collected demographic data, reproductive history, medical data, risk factors for the adverse reproductive outcome (environmental and occupational exposures, lifestyle), and data regarding the evolution and outcome of the last recognised pregnancy. The questionnaire also collected detailed information on the job held at the time of the last recognised pregnancy (if the woman was working with ethylene oxide, she was asked to provide a complete list of daily tasks she was performing). Prior to administration, the questionnaire was tested on a small sample of working women. xiv The validity of the questionnaire-collected information on the evolution and outcome of the last recognised pregnancy was assessed by comparing this information against medical records (considered the “gold standard”). The assessment showed that mothers’ recall was accurate for the following variables: medical facility were the pregnancy was recorded, date of the reproductive event, gestation length, vital status of the newborn, number of foetuses, child gender, disease/medical problems during pregnancy and treatment received during pregnancy. There was an error in the mothers’ reporting of the birth weight of their babies. The possible misclassification of outcome resulting from this error was shown to be nondifferential (the proportion of subjects misclassified on outcome did not depend on exposure). Therefore, this misclassification could bias the effect estimate towards the null value or it could not produce any bias at all. The analysis carried out to detect possible associations between exposure to ethylene oxide and adverse reproductive outcomes included 98 of the initial 109 pregnancies on which information had been collected (11 pregnancies were excluded from the analysis for the following reasons: 2 were multiple pregnancies, 4 were conceived before 1st January 1992 and 5 were conceived while the mother was not employed). Amongst the 98 singleton pregnancies included in the analysis, 19 were classified as exposed and 79 as unexposed to ethylene oxide. The relative risk for spontaneous abortion was RR=16.63 (95%CI=1.97-140.42; p=0.004), for stillbirths RR=3.47 (95%CI=0.63-19.01; p=0.18), for pregnancy loss RR=6.24 (95%CI=1.95- 19.93; p=0.003), for low birth weight RR=0.61 (95%CI=0.09-4.30; p=0.51) and for combined adverse reproductive outcome RR=2.09 (95%CI=1.00-4.36; p=0.06). No confounders were detected for any of the associations between exposure to ethylene oxide and the adverse reproductive outcomes under study. For the association between exposure to ethylene oxide and combined adverse reproductive outcome the analysis detected three effect modifiers: paternal age (father aged 40 or older at conception), passive smoking and maternal age (mother aged 35 or older at conception). In conclusion, this study, the first in South Africa on ethylene oxide exposure and adverse reproductive outcomes, confirmed the widespread use of ethylene oxide, exposure to this agent in public sector hospitals and associations between exposure to ethylene oxide and spontaneous abortion and between exposure to ethylene oxide and pregnancy loss (either spontaneous abortion or stillbirth). xv Moreover, the study provided data on reproductive outcomes in employed women (on which scant data are available in South Africa) and added information on the validity of selfreported pregnancy data relative to medical records. The findings of the study support the conclusions of the previous studies that had suggested that exposure to ethylene oxide during pregnancy could lead to adverse reproductive outcomes. The study detected no associations between exposure to ethylene oxide and stillbirth, low birth weight or between exposure to ethylene oxide and combined adverse reproductive outcome.

Frailty and malnutrition are two major medical issues influencing the health of older people. This doctoral thesis investigated the predictive ability and discriminatory power of clinically applicable frailty instruments and their malnutrition counterparts - nutritional screening tools (NSTs). The study was prospective and observational by design, and included patients aged ≤ 70 years consecutively admitted to the Geriatric Evaluation and Management Unit (GEMU) at The Queen Elizabeth Hospital, South Australia. Thesis aims were to: (i) identify the prevalence rates of malnutrition and frailty in hospitalised older people and (ii) determine the predictive ability and accuracy of these measurements. The mean (standard deviation) age of patients was 85.2 (6.4) years; 123 (72 %) were female, n = 172. Malnutrition and frailty prevalence rates were high: malnutrition was found in 53 (31 %) of patients using the Mini Nutritional Assessment (MNA) for classification; and frailty was found in 107 patients (62 %) by the Cardiovascular Health Study (CHS) frailty index. When looking at nutritional screening tools as predictors of hospital discharge outcomes: the MNA and the MNA-short form (MNA-SF) were associated with length of stay (LOS); the Geriatric Nutritional Risk Index (GNRI) and calf circumference (CC) were associated with functional decline; and mid arm circumference (MAC) was associated with a higher level of care on discharge. At six months post-hospitalisation, malnutrition by the MNA (OR = 3.29) and GNRI (OR = 2.84) was predictive of poor outcome (defined as mortality or admission to high level care). However the discriminative ability of this prediction was inadequate (area under Receiver Operating Characteristic curve (auROC) values were < 0.7). iii Regarding frailty, almost all frailty and functional decline indices were predictive of poor outcome (mortality or high level care admission) at both hospital discharge and at six month post-hospitalisation. However when discriminative ability was considered, only the Frailty Index of Cumulative Deficits (FI-CD) and the adapted Katz score of Activities of Daily Living showed adequate values (auROC values of 0.735 and 0.704 respectively). The FI-CD was the only instrument to show adequate discriminatory power in predicting poor six month outcome (auROC = 0.702, P < 0.001). Malnutrition shares many characteristics with frailty; however the overlap between these two conditions lacks a quantitative foundation. Therefore, this doctoral project also looked at the efficacy of nutritional screening tools as frailty indices in hospitalised older people. An additional focus of this thesis was the association between appetite, body composition and inflammation in healthy people of all ages. This thesis illustrated the high prevalence rate of both malnutrition and frailty in hospitalised older people. Results highlight the importance of research into the predictive ability of both NSTs and frailty instruments in hospitalised older people. Such knowledge will be of assistance in the areas of gerontology research, clinical practice and public health policy, particularly in the wake of the global expansion of the number of older people. Thesis results may also assist in standardising definitions for both frailty and malnutrition, definitions which are greatly needed in clinical practice and research.<br>Thesis (Ph.D.) -- University of Adelaide, Adelaide Medical School, 2013

Abstract Objectives: This research project was undertaken to review two commonly used screening instruments for the elderly who attend at hospital emergency departments in Ontario. These instruments were then contrasted with a new potential screening instrument made up of items drawn from the Minimum Data Set-Acute Care instrument (MDS-AC Version 1_CAN). The hypothesized outcome was better specificity and sensitivity utilizing the newly prepared instrument in predicting at an earlier point if an elderly emergency department patient would become an alternate level of care (ALC) patient. The ability of the screener to predict negative outcomes (delirium, longer length of stay) was also analyzed. Methods: One dataset from a previous International Resident Assessment Instrument (interRAI) organization study in southern Ontario completed in 2000 was utilized to inform this research. Each of the commonly used screening instruments was crosswalked to the MDS-AC items, then both univariate and bivariate analyses were completed. Three research questions were then posed. By testing various logistic regression models, the research looked to establish whether the newly developed instrument would be able to perform comparably to the other two currently-used instruments, and whether it would be more effective in predicting ALC status and particular adverse patient outcomes. Results: The newly-developed instrument was found to perform more accurately. While several variables were tested, a core number were found to be more strongly predictive of future need for ALC status. Conclusions: Future research in this area is recommended.

Objectifs: Les données provenant des centres de soins tertiaires suggèrent que le taux de mortalité péri-opératoire (MPO) après cystectomie notés pour les patients âgés (septuagénaires et octogénaires) n’excède pas celle des patients plus jeunes. Toutefois, les données provenant de la communauté démontrent un phénomène inverse. Spécifiquement, la MPO est plus élevés chez les ainés. Dans cette thèse nous allons présenter une réévaluation contemporaine du taux de MPO après cystectomie. Méthodes: Entre 1988 et 2006, 12722 cystectomies radicales pour le carcinome urothéliale de la vessie ont été enregistrées dans la banque de données SEER. Le taux de MPO a été évalué dans les analyses de régression logistique univariées et multivariées à 90 jours après cystectomie radicale. Les covariables incluaient: le sexe, l’ethnie, l’année de chirurgie, la région d’origine du patient ainsi que le grade et le stade de la tumeur. Résultats: Parmi tous les patients, 4480 étaient des septuagénaires (35.2%) et 1439 étaient des octogénaires (11.3%). Le taux de MPO à 90 jours était de 4% pour la cohorte entière vs. 2% pour les patients moins de 69 ans vs. 5.4% pour les septuagénaires vs. 9.2% pour les octogénaires. Dans les analyses de régression logistiques multivariées, les septuagénaires (OR=2.80; <0.001) et les octogénaires (OR=5.02; <0.001) avaient reçu un taux de MPO plus augmenté que les patients moins de 70 ans après une cystectomie radicale. Conclusion: Cette analyse épidémiologique basée sur les donnés le plus contemporaines démontre que l’âge avancée représente un facteur de risque pour un taux de MPO plus élevé.<br>Objective Data from tertiary care centers suggest that the perioperative mortality (POM) after radical cystectomy (RC) is not different in septuagenarian or octogenarian patients, compared to younger individuals. Conversely, population-based data state otherwise. We revisited this topic in a large contemporary population-based cohort. Methods Between 1988 and 2006, 12722 radical cystectomies were performed for urothelial carcinoma of the urinary bladder (UCUB) in 17 Surveillance, Epidemiology and End Results (SEER) registries. Of those 4480 were aged 70-79 and 1439 were 80 years and older. Univariable and multivariable logistic regression models tested 90-day mortality (90dM) after radical cystectomy. Covariates consisted of gender, race, year of surgery, SEER registry, histological grade and stage. Results Of all 12722 patients, 4480 (35.2%) were septuagenarian and 1439 (11.3%) were octogenarian. The overall 90dM rate was 4% for the entire population, 2% for patients aged 69 years or younger, 5.4% for septuagenarian patients and 9.2% for octogenarian patients. In multivariable logistic regression analyses, septuagenarian (OR= 2.80; <0.001) and octogenarian (OR= 5.02; <0.001) age increased the risk of 90dM after RC. Conclusions In this population-based analysis, POM was between 3 and 5-fold higher respectively in septuagenarian and octogenarian patients which is higher in tertiary care centers. This information needs to be included in informed consent considerations, specifically if RC will not be performed at a tertiary care center.

Purpose: The purpose of this dissertation was to examine the determinants of unplanned emergency department (ED) use by home care clients, the profile of older ED patients, their transitions from the ED, as well as the determinants of post discharge outcomes among older ED patients. The goal of this dissertation was to create theoretically driven, evidence-based, and practical risk identification methods for home care and the ED. Methods: First, a multi-year, census-level cohort study was conducted on home care clients in two Canadian provinces (N=617,035). Census-level data from RAI-HC assessments were linked to census-level ED records. A needs-based decision tree model – the ED Model – informed by the Andersen Behavioural Model, was created using decision tree analyses. The final model was validated on a separate data partition and compared to the ERA Index and the CARS. Multilevel analyses were conducted to test regional variation in model performance. Disease stratified analyses were also conducted to test model generalizability across common disease classes. Regression analyses determined the effect of predisposing and enabling factors within ED Model strata. Second, a multi-site, multi-province prospective cohort study was conducted, termed the Management of Older Persons in Emergency Departments (MOPED) Study, using a clinically representative sample of 2,101 older ED patients. The interRAI ED-CA was used to assess older ED patients, and a 90-day disposition was collected. The profile of older ED patents was examined. Best-subset regression analyses identified person-level determinants of acute inpatient admission. Two needs-based decision tree models – the ALC/LTC and ED Revisit Models – were created using decision tree analyses to determine the risk of ALC designation or LTC placement, and unplanned repeat ED visits, respectively. Both models were validated on separate data partitions. Multilevel analyses were conducted to test site-level variation in the models’ performance. Results: Overall, 41.2% of home care clients had at least one unplanned emergency department visit within 6 months of an assessment. Previous ED use, cardio-respiratory symptoms, cardiac conditions, and mood symptoms featured heavily in the ED Model. The ED Model provided moderate risk differentiation and clinical utility. It achieved an area under the curve of 0.62 (95% CI: 0.61-0.62) and showed clear differentiation in Kaplan-Meier plots using validation data. Multi-level analyses showed no regional variation. The ED Model significantly outperformed the similar tools specific to primary care with respect to overall accuracy and perceived clinical utility. Predisposing and enabling characteristics provided little added differentiation beyond evaluated need. The majority of older ED patients were dependent on others for basic tasks of daily living, and many had fragile informal care or lived alone. Triage acuity generally did not differentiate chronic geriatric disabilities and conditions. Previous ED or hospital use was associated with chronic geriatric disabilities and conditions as well as informal caregiver distress. The Admission Model found that multiple factors were associated with admission to inpatient acute care, including: acuity, instability, changes in ADL function, cognition, nutrition, and anhedonia. Overall, 20.7% of older ED patients admitted to acute care were designated ALC or discharged to LTC; whereas 39.5% of older ED patients discharged home had one or more repeat ED visits within 90 days. Cognitive, functional, and informal care indicators were predictive of ALC/LTC; whereas functional status and symptoms were predictive of repeat ED use. The ALC/LTC and ED Revisit Models provided good risk differentiation, achieving AUC’s of 0.74 (95% CI: 0.69-0.79) and 0.69 (95% CI: 0.63-0.74), respectively. The ALC/LTC and ED Revisit Models showed clear differentiation in Kaplan-Meier plots. Multi-level analyses showed no site-level variation in each models’ performance. Conclusions: This dissertation produced tangible and empirically-based risk assessment models for clinical practice in home care and the ED. The models developed in this dissertation can support the targeting of preventative services as well as better communication strategies between the ED and community supportive care, primary care, and inpatient acute care. Key questions related to the prevention of the risk pathways identified in each risk assessment model remain unanswered, and should be a focus of future research.