Doctor of Philosophy in Population and Public Health (PhD)
Understanding acute care utilization and health outcomes among sexual minorities with substance use disorder
Background: In 2002, British Columbia (BC) began redistributing its hospital services. Existing facilities closed, were downsized or became specialized. Reasons for these changes included the centralization of the health authorities and subsequently the redistribution of services, along with safety concerns regarding small units, difficulties recruiting and retaining staff, and policy changes in the province’s Standards of Accessibility. At the same time, innovations in service delivery, such as inter-hospital transfer practices and telehealth initiatives (e.g. telestroke), modified how health care is provided. Effective health service delivery is a complex matter. Over a decade since redistribution began, there has been no evaluation of the changes in service distribution and their impact on patient health.Methods: This is a retrospective cohort study of all adult (18 years and over) acute myocardial infarction (AMI), stroke, and severe trauma events that occurred within the province between April 1 1999 and March 31 2013. Using administrative data, segmented regression and hierarchical hazards modelling techniques, this study examines the effect of service redistribution on patients’ mortality outcomes.Results: The interrupted time series models found service redistribution was not associated with changes in 30-day mortality outcomes, and was likely a response to facility underutilization. Although there was extensive variation in patient access to care (travel burden) across health authorities, the hierarchical Cox proportional hazards models showed that long travel time (>30 mins) was not associated with patient short term mortality after controlling for appropriateness and quality of care along with compensating mechanisms such as inter-hospital transfers, and telehealth services.Conclusion: This work demonstrates that efficiencies in health system delivery can be gained by eliminating underutilized acute care services but also identifies challenges in ensuring equitable access to care.
Introduction Early detection and management, as outlined in dementia guidelines, can improve outcomes and potentially reduce the number of transitions experienced between care-facilities. The objectives of this thesis were to : conduct a critical assessment of the literature on actual versus guideline-consistent dementia care; use population-level data to examine variations in receipt of guideline-consistent dementia care; understand longitudinal patterns of transitions and the factors that contribute to transitions; and assess if receipt of guideline-consistent dementia care and/or high quality primary care are associated with the number of transitions experienced. MethodPopulation-level administrative data in British Columbia were used to identify cohorts of individuals newly diagnosed with dementia in 2001/02 and 2009/10. Dementia guidelines were used to characterize clinical care individuals could receive. The proportion of patients diagnosed with dementia in 2009/10 who received guideline-consistent dementia care and the probability that patient characteristics affected the likelihood of receiving each process was assessed. Those diagnosed with dementia in 2001/02 were followed forward 10-years after the first point of diagnosis and points of care when transitions were highest as well as factors that contribute to those transitions were assessed. The association of receipt of guideline-consistent dementia care and/or high quality primary care with the number of transitions experienced in the year of diagnosis was assessed using negative binomial regression. ResultsOlder patients were less likely to receive guideline-consistent dementia care. A quarter of the cohort received an antipsychotic or non-recommended benzodiazepine. Individuals living within rural health-authorities or of low income were more likely to receive antipsychotic treatment. Transitions were highest in the year of diagnosis and at end-of-life, driven by acute hospitalizations. Higher morbidity, living within rural health-authorities, and having behavioural symptoms associated with dementia were strongly associated with the number of transitions experienced. Lastly, receipt of guideline-consistent dementia care and high quality primary care, independently, were associated with fewer transitions across care settings. ConclusionPatterns of inequality by age and income may signal barriers to guideline-consistent dementia care. The spike in transitions in the year following diagnosis highlights a distressing period for individuals with dementia, but suggests a useful target for interventions.
Amidst concerns about escalating health spending, examining variation in health care delivery may reveal opportunities for improved efficiency. Influential research in the United States (US) has concluded that health care spending and service use vary substantially from place to place, and this cannot be explained by differences in the health status of populations or by better outcomes of care in higher-spending regions. Whether similar patterns exist in Canada is not clear. This thesis uses administrative health data to examine how and why health care use and costs vary within the Canadian province of British Columbia (BC). We developed networks of patients, physicians, and hospitals that correspond to actual service use, in order to ensure that observation of variation was not obscured by unit of analysis. We also identified areas of the province representing distinct health service environments, as an improvement over existing urban/rural classifications in understanding the role of geographic context. Access to individual-level data allowed more complete adjustment for population characteristics than is typically possible. In contrast to the US, this thesis suggests that variation in costs of physician and hospital services in BC is largely explained by population health status. The very different environments for health services that exist among metropolitan, non-metropolitan, and remote regions of the province also explained some area-level variation. Despite modest variation in total costs, there are clear differences in patterns of service use across the province due to substitution between categories of care (such as inpatient and outpatient, or generalist and specialist services). Though differences in costs are modest, marked differences in health outcomes are evident, and require further scrutiny. Results show there are no areas with systematically higher volume or more intensive service provision for populations with similar health needs. However, this does not mean that important variation does not exist and cannot be uncovered. It may be that examining variation at the level of provider, among population groups, or in treatment for specific diseases or conditions will yield more actionable results. Ultimately policy reforms aimed at system-wide quality and efficiency, rather than targeted at high-spending regions, will likely prove most promising.
Background: Highly active antiretroviral therapy (HAART) has transformed HIV from a once fatal condition into a treatable chronic disease. As people with HIV are living longer than in the past, understanding the effects of aging with HIV is of increasing importance. This dissertation aims to explore trends of several chronic diseases during the current HAART era, while also taking into consideration the impact of expanded access to HAART in British Columbia, Canada from 2000-2012. Methods: The studies presented in this dissertation are based on administrative data collected from the Comparative Outcomes and Health Service Utilization Trends (COAST) study. Various analytical methods were used to assess trends of chronic disease incidence of six common chronic diseases: cardiovascular disease (CVD), chronic obstructive pulmonary disease (COPD)/asthma, diabetes mellitus (DM), hypertension (HTN), chronic kidney disease (CKD) and chronic liver disease (CLD). Both studies were retrospective population-based cohort studies of HIV-positive individuals whom accessed HAART and identified as HIV-positive in the COAST study database by validated algorithms. Several measures were employed to determine risks and trends of chronic disease incidence. Results: The results of each study showed that trends and risks of chronic disease incidence were not all consistent. In the first study exploring trends of chronic diseases among 10,210 HIV-positive individuals whom had accessed HAART the adjusted incidence rate for HTN increased over time; CKD and CLD decreased over time; and no trend was observed for CVD, COPD/Asthma and DM. In the second study, among 4,840 HIV-positive individuals who initiated HAART during this period, the relative risk of CLD incidence was reduced in the post- (2006-2012) versus pre- (2000-2005) HAART expansion periods. The relative risk for CVD, DM, HTN, COPD/asthma and CKD were not statistically significant in the post expansion period. Conclusions: Results from this dissertation provide insight on trends and risks of several comorbidities during the current HAART era. Specifically, the results of this dissertation highlight the trend towards increasing incidence of HTN and decreasing incidence of CLD among HIV-positive aging populations. Understanding how chronic comorbidities affect future disability and death among people aging with HIV is an important area of further research.