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Graduate Student Supervision
Doctoral Student Supervision (Jan 2008 - May 2021)
Opioid use disorder (OUD) is a chronic health condition that exposes people to harms (e.g., overdoses) that can be mitigated by treatments, such as oral methadone. For people not benefitting from such oral treatments, evidence supports the use of injectable opioid agonist treatment (iOAT) with diacetylmorphine or hydromorphone, which has recently begun expanding in Canada. While iOAT was rigorously tested in clinical trials, research questions were motivated towards testing the effectiveness of medications. This leaves critical questions about other salient attributes of iOAT (e.g., daily interactions with health care providers) and patients’ experiences when iOAT is offered as a regular clinical program. Addressing these gaps was the broader aim of this research. This multi-method research was conducted alongside a longitudinal cohort study of people with OUD who were currently or previously receiving iOAT in Canada’s first clinical program. A qualitative study explored participants’ experiences in iOAT as they related to patient-centered care (i.e., holistic care, individualized care, collaborative care, therapeutic relationships). Next, a thematic analysis was conducted on eight waves of participants’ positive and negative perceptions of iOAT. These studies supported framework development for a quantitative analysis of participants’ treatment satisfaction trajectories and its relationship with patient and program characteristics. The qualitative research revealed two inter-related processes: ‘meeting me where I am’ highlighted participants’ initial reasons for seeking iOAT and the unique unraveling of individualized and holistic care needs. The second process ‘building health care provider relationships’ revealed the significance of therapeutic relationships and how these were formed through “opening up” and “being a part of care”. The salience of therapeutic relationships was also shown in the thematic analysis, where they represented 23% of positive and 12% of negative comments overall. The analysis of treatment satisfaction trajectories determined that the extent of drug liking and unfavorable health care provider interactions held the strongest independent effects on overall satisfaction over time. This research demonstrated that therapeutic relationships played a fundamental role in participants’ unique iOAT needs and treatment satisfaction over time. These findings urge an expanded vision of treatment implementation and monitoring for OUD.
Background: Injectable opioid agonist treatment with hydromorphone (a licensed opioid analgesic) or diacetylmorphine (pharmaceutical grade heroin) is effective at reducing illicit opioid use and improving health and social functioning among patients with opioid use disorder. Concurrent cocaine use is prevalent among patients receiving injectable opioid agonist treatment, however modest declines have been observed in the proportion of patients using cocaine and in the number of days of cocaine use while engaged in treatment. To date, studies have not explored what processes might explain these reductions, or how patterns of cocaine use might vary over time at the intra- and inter-individual levels. Methods: This study was conducted with patients receiving daily injectable hydromorphone or diacetylmorphine for the treatment of opioid use disorder at a clinic in Vancouver, Canada. The qualitative analysis was guided by a grounded theory approach involving one-on-one patient interviews (n=31). Findings directed covariate selection for the quantitative analysis. The profile of participants using cocaine was characterized (n=166), and multilevel models were used to explain variation in cocaine use over 24-months, using data from a baseline visit and six follow-up visits.Results: Qualitative analysis revealed that access to injectable opioid agonist treatment promoted the self-management of cocaine use. Participants distanced themselves from the street environment, made efforts to “control” their cocaine use, and sought supports to bolster these efforts. Quantitative analyses identified significant intra- and inter-individual variation in cocaine use over 24-months. On average, cocaine use decreased over time, however the rate of change varied from one participant to the next. Women reported more cocaine use than men, and participants with more lifetime years of cocaine use at baseline reported more cocaine use over 24-months. Conclusions: This research highlights heterogeneity in patterns and processes of cocaine use. Intra- and inter-individual variation in cocaine use was identified, and was explained by participant characteristics, including demographics and substance use histories. Given daily contact with care, injectable opioid agonist treatment serves as an optimal setting to integrate treatments for cocaine use disorder. Care providers can communicate with patients about their patterns of cocaine use and associated characteristics to guide treatment plans.
Birth weight discordance and sex discordance are two major predictors in identifying adverse fetal, neonatal and maternal outcomes in twin gestation. No study to date has comprehensively studied the role of these predictors together and in relation to placenta and cord. We analysed data from a large population-based sample of 10 years twin deliveries born in British Columbia and compared the result with a hospital-based sub-sample, taking chorionicity information into account. The unique aspect of our study is the use of a large population-based sample, generalized equation modeling, a wide range of confounding variables and analysing chorionicity and pathological aspects of placenta and cord in relation to growth and sex discordance.Aberrant growth among twins was related to unequal placenta sharing, existence of anastomosis between superficial vessels on the placental surface, length of umbilical cord and type of cord insertion. Fetal sex is an important predictor in placental findings including anastomosis, unequal placenta sharing, placental lesions and placental inflammation.Receiver operating characteristic analysis revealed that a threshold level of ≥30% had the optimal accuracy to detect perinatal mortality irrespective of chorionicity. Perinatal mortality and morbidity were also associated with growth and sex discordance. Early and late neonatal mortality were more likely in male infants from male-female twin pairs compared with females from female-female pairs. The predictive basis of growth discordance on stillbirth was dependent on fetal sex discordance, fetal growth, parity, gestational age and sizes of the twins. Higher odds of adverse maternal outcomes were found for mothers carrying discordant growth twins compared to the reference category for the following conditions: preeclampsia, pregnancy induced hypertension, preterm labor, premature rupture of membrane, prolonged preterm rupture of membrane, length of stay >3 days and cesarean section. Sex pairing is associated with postpartum length of stay >3 days, proteinuria, pregnancy induced hypertension, preeclampsia and cesarean section. Given that chorionicity information is not available in most datasets, it is reasonable to use sex discordance as a proxy measure. Twin pregnancies can benefit from reliance of clinicians on these data showing the importance of growth and sex discordance in prediction of adverse pregnancy outcomes.
Master's Student Supervision (2010 - 2020)
Background: Opioid dependence is a chronic relapsing disease with a number of related harms. Despite the proven effectiveness of opioid maintenance many men and women are not engaged or retained in this treatment. Accounting for patient perceptions of their interactions with health care providers may offer important evidence as to meeting gender specific heath and treatment needs of this population. Objective: This thesis investigates access to health care and addiction treatment services among long-term opioid dependent men and women. Factors associated with retention to opioid maintenance treatment are explored among participants and stratified by gender. Perceptions of encounters with health care providers as potentially offensive, degrading, or abusive are considered. Finally, the feasibility of sharing study findings with long-term opioid users are explored. Methods: The Gender Matters in the Health of Long-term Opioid Users study is a descriptive cross-sectional study of long-term opioid users in the Downtown Eastside of Vancouver. Descriptive variables were explored and logistic regression models were built to determine associations between independent variables and the opioid maintenance treatment retention and perceived abuse in health care outcomes. Two formats of sharing study findings with participants were piloted and participant perceptions of study findings and the meeting formats were gathered. Results: Rates of opioid maintenance treatment retention were similar among men and women while factors associated with retention differed by gender. Half of participants reported perceived abuse in health care, which was associated with childhood maltreatment and psychological health problems. The majority of participants felt it was important for participants to be involved in knowledge translation, while few had previously had the opportunity to do so. Conclusions: Gender, along with other structural factors have strong implications for the appropriateness and success of the treatment and models of care provided to opioid-dependent men and women. Patient histories and perspectives must be accounted for to determine suitable treatments and to ensure health care encounters are not perceived as offensive, degrading, or abusive. The involvement of participants in knowledge translation can serve as a means of empowering participants and accounting for patient voice in recommendations for service provision and policy.