Doctor of Philosophy in Population and Public Health (PhD)
The relationship between illicit stimulant use and treatment outcomes among patients receiving supervised injectable opioid assisted treatment in Vancouver
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.
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.