Relevant Thesis-Based Degree Programs
Affiliations to Research Centres, Institutes & Clusters
Graduate Student Supervision
Doctoral Student Supervision
Dissertations completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest dissertations.
Improving referrals to rheumatologists for patients with inflammatory arthritis (2024)
Background: There are two broad types of arthritis, and patient care differs by type. Those with inflammatory arthritis (IA) should be treated by a rheumatologist within 12 weeks of symptom onset, while those with non-IA, can benefit from multi-disciplinary care and lifestyle modifications. No standard referral tools are used to help primary care physicians (PCP) direct people with joint pain to the appropriate healthcare provider. Many patients wait needlessly, sometimes in the wrong queue, increasing their chances of disability.Objectives: First, to understand recent trends in patient referrals to rheumatologists in British Columbia (BC). Second, to identify and test the accuracy of a patient-completed questionnaire to classify and prioritize patients with IA for referral from primary care to rheumatologists and seek the perspectives of patients and rheumatologists for implementation considerations.Methods: Using administrative databases from Population Data BC, current rheumatology referrals trends were examined. A scoping review was performed to identify validated questionnaire(s) to evaluate in a BC clinical study: The Patient Self-Administered Inflammatory Arthritis Detection (SAID) study. A multi- and mixed methods approach was used to gain user perspectives of barriers and opportunities to implement a questionnaire in the referral pathway.Results: Rheumatology referral trends in BC showed long wait times for patients with IA and a high proportion of referral of patients with non-IA. Access improved between 2010-2020 but remained long, particularly for females and people living outside of metropolitan areas. The scoping review identified 53 studies of referral tools. Two tools were selected for The Patient SAID Study; the Early Inflammatory Arthritis Questionnaire (EIAQ) and the Case Finding Axial Spondyloarthritis (CaFaSpa) questionnaire. The reported EIAQ performance was not replicated, but a new, preliminary scoring algorithm, that added a back pain question, had promising performance (AUC=0.740, 95%CI 0.632-0.849) suggesting that EIAQ questions were informative. Patients and rheumatologists supported the use of the questionnaire for referrals and provided recommendations for clinical implementation.Conclusions: There is a need to improve the rheumatology referral process in BC and this thesis tested a patient-completed questionnaire that may support that. The findings suggest the potential value of the questionnaire to streamline referrals and access to care.
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Patient-oriented research to support decision-making in pregnancy hypertension (2021)
Background: Pregnancy hypertension is a common, potentially fatal condition. New guidance recommends ‘tight’ control of pregnancy hypertension over ‘less-tight’ control. However, guidance also suggests that treatment recommendations consider patient preferences. This dissertation aims to understand how to support patients and providers to make preference-congruent and informed decisions about pregnancy hypertension management.Methods: First, a mixed-methods study, including a best-worst scaling task, of patient preferences for pregnancy hypertension management was conducted. Next, a systematic review built upon ancillary findings by assessing emotion in patient decision aids (PtDAs) for decisions during pregnancy. Using results from the preferences study, the subsequent study re-analyzed the Control of Hypertension in Pregnancy Study (CHIPS) trial using a patient-oriented composite endpoint. A PtDA was developed and assessed for quality and effectiveness. Lastly, a preliminary study explored emotion-regulation in patient decision-making.Results: The mixed-methods preference study (n=210) found that individuals prioritised seven outcomes when choosing how to manage pregnancy hypertension. Latent class analysis identified three preference profiles (a profile comprises participants with similar preferences). Each profile placed different importance on each outcome: 1) ‘equal prioritisers’ valued the outcomes equally; 2) ‘early delivery avoiders’ prioritised avoiding delivery before 34 weeks; and 3) ‘medication minimisers’ prioritised avoiding medication. A systematic review of 39 PtDAs found that most did not address emotion. Reanalysis of the CHIPS trial using a weighted patient-oriented composite endpoint found that while both strategies yielded equal outcomes for equal prioritisers; ‘tight’ control produced better outcomes for early delivery avoiders; and ‘less-tight’ control produced better outcomes for medication minimisers. A prototype PtDA that incorporated these profiles was assessed (n=99) as very acceptable and clear, and significantly improved knowledge. The preliminary emotion study (n=107) found that individuals’ beliefs about their own ability to regulate emotions may limit the benefit of a PtDA. Conclusions: Patient preferences for management of pregnancy hypertension can be broadly described by three profiles. ‘Tight control’ is well-suited to only two of these profiles, emphasizing the importance of shared decision-making in reaching treatment decisions. A PtDA for pregnancy hypertension may help patients make more informed decisions. Future work should explore how to include emotion in PtDAs.
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Comparative efficacy and safety of first-line treatments for hiv patients for clinical guideline development and the impact of individual patient data (2019)
Since 2008, efavirenz+tenofovir+emtricitabine (EFV+TDF+XTC) has been the preferred first-line antiretroviral therapy (ART) regimen for treating HIV throughout most countries. With an expanding choice of ART, should a newer treatment be preferred? The therapeutic landscape was assessed for efficacy, safety and tolerability through a systematic literature review (SLR) and network meta-analysis (NMA). Data were analyzed using aggregate data (AgD) from publications for each population of interest. Ninety eligible trials were identified in the principal SLR and 65 were included in analyses. There was high certainty that dolutegravir (DTG) was superior to EFV with respect to viral suppression, change in CD4 cell counts, discontinuation, and adverse events. DTG and EFV were comparable among TB-HIV co-infected patients. Among pregnant women initiating DTG, there appeared to be fewer adverse events than with EFV. To determine whether the inclusion of individual patient data (IPD) would impact decision-making and to explore the impact of integrating IPD in varying ways, the SLR and NMA were expanded through the addition of IPD obtained for three critical trials: SINGLE, FLAMINGO and SPRING-2. Use of IPD did not alter the conclusions. In the few cases where IPD-based analyses were selected, the impact on estimates did not meaningfully impact their utility towards the development of clinical guidelines. A simulation study was conducted to determine how network size, density, proportion of IPD, and nature of effect-modification could predict impact of IPD on NMA results. The inclusion of IPD may be most impactful among small and/or sparse networks of evidence. Having a higher proportion of treatment comparisons with IPD also improves the NMA estimates, particularly among larger networks of evidences. Similarly, these simulations suggested while inclusion of IPD led to improvements with respect to both bias and precision of estimates, these improvements decreased within larger and more dense networks – such as those used in the HIV analyses. In conclusion, the findings support the use of DTG+TDF+XTC as the preferred first-line regimen, supporting the change in HIV guidelines by the World Health Organization in late 2018. The analyses provide important insights into the types of networks where IPD would influence results of NMA.
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Development and application of a whole disease model of oral cancer to inform health technology management (2019)
Whole Disease Models (WDMs) are decision analytic models characterized by their ability to reflect the policy changes that occur at multiple points within the entire clinical trajectory of a given disease. They differ from conventional ‘piecewise’ modeling approaches in their ability to reflect processes that occur ‘upstream’ and ‘downstream’ from a technology decision of interest. This dissertation describes the development of a WDM of oral cancer, and its application in generating evidence to inform Health Technology Management (HTM).The dissertation reviews the available scientific literature concerning health economic decision analytic modeling in oral cancer, and argues that a Whole Disease Model approach is appropriate for economic evaluation in this disease. A conventional piecewise Markov model is used to evaluate the cost-effectiveness of risk-guided management of oral premalignancy, and the limitations of that approach are discussed. The dissertation then describes the development and validation of the Whole Disease Model of Oral Cancer (WDMOC). The WDMOC is used to re-evaluate the risk-guided management policy, and how the cost-effectiveness of such a policy is influenced by upstream (tobacco/alcohol cessation, improved screening) and downstream (improved surgical treatment for early-stage disease, improved systemic therapy for late-stage disease) policy changes, including the hypothetical effect of a population HPV vaccination program. The WDMOC found that risk-guided management was cost saving compared to current standard practice, but was not expected to produce gains in quality-adjusted life years (QALYs). The cost-effectiveness of a risk-guided management approach was affected by upstream factors that influence malignant progression and downstream factors that prolonged survival among advanced cancers. Scenario analysis was used to estimate the impact of multiple simultaneous policy changes on the cost-effectiveness of a risk-guided approach. The WDMOC contributes a useful platform for economic evaluation that can inform HTM. Results of the analysis suggest that a risk-guided approach is cost-effective, particularly among patients with regular access to a dentist that regularly performs oral cancer screenings and in the presence of improved options for managing late-stage disease. The WDMOC was developed using an open source approach so that it can readily incorporate new information and have users in multiple policy jurisdictions.
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Economic evaluation of interventions to support shared decision-making: an extension of the valuation framework (2018)
Background: Supporting shared decision-making (SDM) between patients and providers is a key health care objective. SDM-interventions can help encourage SDM but may require investment. This thesis used a case study of treatment decision-making for advanced osteoarthritis to quantify the economic value of SDM-interventions in health care. Methods: A trial-based cost-effectiveness analysis and a longer-term cost analysis using administrative data was undertaken to estimate the value of a SDM-intervention in adults considering total joint arthroplasty. Limitations of conventional cost-effectiveness analysis in assessing the consequences of SDM-interventions were outlined, and methods for valuing the process of SDM presented. A systematic review of discrete choice experiments (DCEs) that have valued the process of SDM was undertaken. A two-step chained valuation technique which included a DCE was completed to estimate the health state utility value of the process of SDM.Results: The trial-based cost-effectiveness and administrative data analyses suggested that SDM-interventions for total joint arthroplasty provided value, resulting in lower costs at two and seven-years follow-up and similar quality-adjusted life-years (QALYs) over the two-year trial period. QALYs may fail to capture the consequences of SDM-interventions, such as the value of being informed and involved in decision-making. To reflect the opportunity cost of allocating scarce resources toward these non-health benefits, Canadian guidelines suggest that their value be ascertained through the trade-off with health outcomes using societal preferences. The systematic review found 25 studies that have valued SDM using a DCE. No studies valued SDM in advanced osteoarthritis, and most did not include a health outcome attribute or elicit societal preferences. Analysis of the data from the DCE completed by nearly 1,500 Canadians aged 60 and older revealed that respondents were willing to sacrifice health outcomes for greater SDM and estimated the value of SDM.Conclusions: Evidence suggests that SDM-interventions for adults with advanced osteoarthritis are a cost-effective use of resources. Results from the trial-based cost-effectiveness analysis, systematic review, and DCE suggest that policy-makers may be justified in allocating scarce resources toward SDM-interventions at the expense of other interventions that provide health benefits. Future research is required to quantify the value of SDM-interventions in other contexts.
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Medication adherence among adult asthma patients: investigating the role for shared decision-making (2017)
Background: Shared decision-making (SDM) has been suggested as a means to improve communication between patients and their healthcare providers, with the purposes of improving multiple asthma-related health outcomes. Despite mounting evidence that suggests potential benefits attributable to SDM, clinical uptake has been slow. Objectives: The purpose of this dissertation is to ascertain the role of SDM in asthma management, to determine the extent to which SDM is currently being implemented into regular asthma care, and to suggest clinical implementation strategies that may facilitate SDM implementation in BC.Methods: This project consists of a) a systematic review of physician attitudes toward SDM, b) a comprehensive narrative literature review to describe the proposed role of SDM in asthma, c) a population level analysis to explore variation in adherence to controller medication, as well as d) an online survey of 117 adult asthma patients living in BC. Results: Results of this work show that in general a) physicians support the use of SDM in various clinical practice scenarios, b) there is a clear role for SDM in treating asthma patients with the goal of reducing the burden of controller medication non-adherence, and c) adherence to controller medications is sub-optimal, with little variation being explained at the population level. The patient survey (d) provided additional insight into this research agenda by showing that while patients prefer to be actively involved in treatment decision-making, there is substantial variation in the extent to which asthma patients are being engaged in their care. Furthermore, multiple predictors of adherence that can be addressed during the clinical encounter (e.g. medication-related concerns) were shown to impact self-reported treatment adherence. Conclusions: The results of this project provide further support for the use of SDM in regular care of asthma patients. I conclude by highlighting the importance of addressing issues related to adherence in an individual and ongoing basis, the value of increasing awareness about the use of SDM, and the potentially valuable role of engaging non-physician caregivers in future SDM implementation efforts. These findings may guide future research investigations regarding SDM uptake and efforts to reduce the disease burden of asthma.
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Master's Student Supervision
Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.
Evaluating the incremental value of patient-reported outcome measures in predicting unplanned hospital readmission or mortality (2024)
Background: Hospital readmissions significantly impact patient outcomes and healthcare costs globally. While prediction models are widely used to identify patients at high risk of readmissions, their discriminative ability often falls short of achieving adequate accuracy. Integrating patient-reported outcome measures (PROMs) may enhance these models by considering patient perspectives on their own health conditions.Objective: To investigate the contribution of PROMs to the performance of prediction models for hospital readmissions by (1) systematically reviewing the literature on readmission prediction models, (2) assessing the incremental value of incorporating PROMs on the performance of risk prediction models, and (3) exploring extra predictive value of PROMs across various clinical and geographic subgroups.Methods: A systematic review of readmission risk prediction models that included PROMs was conducted through searching electronic databases. A retrospective population-based cohort study was performed using data from the British Columbia Acute Inpatient Survey linked to administrative healthcare databases. The study cohort comprised patients discharged from acute care facilities between September 2016 and March 2017 who had completed PROMs. Subgroups were stratified by the presence of ambulatory care sensitive conditions and distance from major hospitals relative to patients’ residences. Prediction models were constructed using both statistical methods and machine learning techniques. Model performance was compared with and without PROMs data for the overall cohort and subgroups.Results: The systematic review highlighted the potential of PROMs in predicting hospital readmission, although the effectiveness varied depending on how PROMs data were collected and used in the prediction models. The analysis included 9,148 patients discharged from BC’s acute care hospitals, with PROMs completed between 26- and 60-days following discharge. While global summary of PROMs were influential predictors, the inclusion of PROM data led to only modest improvement in model performance. Subgroup analyses indicated the need for adjusting risk thresholds to accommodate specific clinical and demographic characteristics.Conclusion: Incorporating PROMs into prediction models for unplanned hospital readmission or death within one year modestly enhanced model performance. However, the marginal gains in predictive accuracy must be balanced against the benefits to patients and the costs associated with collecting these data.
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How a biosimilar switching policy impacted healthcare resource utilization and cost in British Columbia (2024)
The uptake of biosimilars has been slower than hoped in many jurisdictions across the globe. A concern has been raised that switch from originator to biosimilar would be associated with increased health care resource utilization (HCRU) such as increased physician visits and hospitalizations. However, the signals for these concerns have been based on small samples and potentially biased methods. In this study, administrative data were analyzed from British Columbia (BC), Canada where in the past 5 years, policies have led to patients with inflammatory bowel disease (IBD), inflammatory joint disease (IJD), and inflammatory skin disease (ISD) being switched from an originator to a biosimilar to maintain insurance coverage.A literature review was conducted using Embase, Medline, and Web of Science to update existing systematic reviews. HCRU and cost from current literature were summarized. An empirical analysis was undertaken using population-based, administrative databases (Population Data BC) from 2015 to 2021 including individuals with IBD, IJD and ISD based on ICD-9 and -10 codes. The cohort included those using originator TNF-α blockers (adalimumab, etanercept, or infliximab) before the mandatory switch policy. Descriptive analysis of HCRU components (physician visits, hospital days, emergency visits, and other medications) was conducted. An interrupted time series was used to assess the pre- and post-switch trend by treatment and cohort on total HCRU related costs.The literature review showed no pattern in increase HCRU and cost following a switch policy. The analysis on BC population included 6326, 6205, and 2474 patients in the IBD, IJD, and ISD cohorts, respectively. Based on descriptive statistics and interrupted time series analysis, no important changes in physician visits, hospital admission, or emergency visits following the policy occurred for all three cohorts. Overall, no important changes in HCRU costs due to the switch were observed, but a historical trend in decreasing hospitalizations in IBD cohort was identified.This study suggests concerns about biosimilar switch policies creating increases in other HCRU is unfounded in IBD, IJD, and ISD patients. Policy makers in other jurisdictions can feel reassured that mandatory biosimilar switching polices should not lead to increases in the cost of other healthcare resources.
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How do current approaches to communicating ambiguity in risk estimates influence decisions? (2018)
Background: Uncertain outcomes are an unavoidable fact of medicine. First-order uncertainty (e.g. “10 in 100 people can expect an outcome in the next year”) has well-established guidelines as to how it should be best presented, but it is not clear if and how to present second-order uncertainty, referred to as ambiguity (e.g. “10 [95% CI 5,15] in 100”).Objectives: To explore the ways in which ambiguity in risk is currently being described to patients by (1) identifying existing presentation techniques and evidence for their potential impact on decision-making, (2) investigating how presentation techniques influence decision-related outcomes, including intention, trust, worry, decisional uncertainty, risk perception, knowledge and preference, and (3) determining which techniques should be investigated further.Methods: The literature on current techniques to present ambiguity was systematically reviewed through an electronic search of the Medline/PubMed database, and an existing database of patient decision support interventions. The influence of each identified communication technique was evaluated by the design and implementation of a web-survey in a hypothetical atrial fibrillation vignette.Results: Nine distinct presentation techniques were identified as having been used in the past, and were shown to influence decision-making outcomes. Of these techniques, the visual and textual range techniques were found to result in change in intention (in both directions) which was statistically significant, while other techniques decreased trust, increased decisional uncertainty, and resulted in greater knowledge.Conclusions: Techniques that resulted in the worst knowledge of the range in risk scores tended to be the ones that were preferred by participants. Yet, without good knowledge of risks involved with different medical options, informed consent, and value-based decisions are challenging. Findings from this work indicate that some techniques for presenting uncertainty, such as the visual and textual range techniques, impact various psychometric outcomes related to decision-making, including intention to take oral anticoagulation, trust in risk estimates, decisional uncertainty and knowledge of ambiguity. Further research should focus on testing the influence of these techniques on decision-making related outcomes.
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Economic considerations of patient decision aids: a case study in sleep apnea (2014)
Background: Patient decision aids (PtDAs), tools used to facilitate shared decision-making, help improve patient-physician communication and the quality of healthcare decisions. Over 500 PtDAs are available, yet implementation of these tools has been limited. In order for decision-makers to implement new health care interventions such as PtDAs, they require rigorous economic evidence demonstrating that such interventions provide value for money.Objectives: To explore the economic consideration of PtDAs by (1) systematically reviewing PtDA trials that have evaluated economic outcomes, (2) exploring the potential cost-effectiveness of a PtDA for individuals with obstructive sleep apnea (OSA), and (3) describing the development of a an OSA PtDA prototype.Methods: PtDA trials evaluating economic outcomes were systematically reviewed through an electronic search of Medline/PubMed, Embase, CINAHL, and PsycINFO databases. The potential cost-effectiveness of a PtDA for OSA was evaluated through a Markov cohort decision-analytic model, which explored the cost-effectiveness of a PtDA compared to usual care. Finally, an OSA PtDA prototype was developed according to the International Patient Decision Aid Standards (IPDAS) criteria.Results: Our systematic review found that PtDAs will likely increase upfront administration costs, but may decrease short-term costs by reducing the uptake of invasive treatments. Most studies did not comprehensively capture long-term costs and health outcomes appropriately. Through our economic modelling of a PtDA for OSA we found it could be a cost-effective use of resources provided it increases adherence to treatment. However there was considerable uncertainty in this estimate, with expected value of information analysis revealing that additional research is warranted. We developed and tested a prototype OSA PtDA, and found no evidence that users became stuck or experienced errors during usability testing. The majority of users found the PtDA easy to use and worthy of recommending to others.Conclusions: Policy-makers lack sufficient economic evidence to make informed decisions about whether and where to invest in PtDAs. This evidence gap could be a factor contributing to the slow implementation of PtDAs. Using OSA as a case study, this work demonstrates an economic modelling framework that can be used to evaluate the potential cost-effectiveness of PtDAs.
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