Steven Morgan

BACKGROUND: Despite widespread use of contraception worldwide, Canadian research on hormonal contraceptive trends is limited. This thesis aims to address this knowledge gap through an investigation of the levels, trends, and determinants of: (1) hormonal contraceptive use in British Columbia (BC) (Study 1), and (2) the use of cyproterone acetate and ethinyl estradiol (CPA-EE), an acne drug that is also known to be prescribed as an oral contraceptive (OC) despite safety concerns (Study 2). METHODS: This thesis consists of two retrospective analyses of de-identified administrative datasets containing health care, pharmaceutical, and sociodemographic information for residents of BC between 2006–2013, inclusive. Study 1 examined incident and prevalent hormonal contraceptive use in a cohort of reproductive-aged women (15–49 years). Study 2 measured incident off-label use of CPA-EE in women aged 15–34. In both studies, logistic regression was used to model relationships between contraceptive use and sociodemographic factors.RESULTS: Study 1 revealed (1) stable prevalence, but declining incidence of overall hormonal contraceptive use, (2) declining rates of OC use, (3) increased rates of hormonal intrauterine device (IUD) use, and (4) decreased odds of hormonal contraceptive use among Chinese and South Asian women. Despite a decline in use, OCs remained the most popular method, accounting for more than 80% of all hormonal contraceptive use. In Study 2, incident use of CPA-EE declined throughout the study period. South Asian women and women with older physicians (65+) were more likely to receive a potentially inappropriate CPA-EE prescription.CONCLUSION: This thesis contributes to a sparse body of literature on hormonal contraceptive use in Canada. While rates of OC use are declining, hormonal IUD use is increasingly widespread, particularly among younger women. Chinese and South Asian women are less likely to be prescribed OCs and may therefore be at greater risk for unintended pregnancy, although this warrants further investigation, as does the influence of provider characteristics on off-label prescribing patterns.

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Objectives: To examine ethnic and income-related disparities in the use ofantipsychotic medication by conducting a systematic review of the related literatureand a secondary data analysis.Methods: The review was conducted using a protocol developed to systematicallysearch, select and review peer-reviewed articles on ethnic disparities in antipsychoticuse. Study selection and data abstraction were performed by two independentreviewers. The secondary data analysis was conducted to examine income-relateddisparities in antipsychotic use in three cohorts. The first cohort was comprised of 19 to64-year olds who had a recorded schizophrenia diagnosis. Income-related differences inthe essential use of antipsychotics were assessed in this cohort. The second cohort wascomprised of seniors (65 years and older) who had a recorded dementia but notschizophrenia or bipolar disorder diagnosis. The third cohort was of children and youth(18 years and younger) who had no recorded schizophrenia or bipolar disorderdiagnosis. Income-related differences in the potentially inappropriate use ofantipsychotics were studied in these last two cohorts. Disparities in antipsychotic usewere assessed using logistic regression, adjusting for factors that influence medicine use(i.e., age, sex, health status, relevant diagnoses and residence in urban areas).Results: The systematic review found no consistent evidence of ethnic disparities in thereceipt of antipsychotic treatment. However, among those who were treated, ethnicminorities were found to be consistently less likely than non minorities to receive thenewer type of antipsychotics. Results of the secondary data analyses indicate that theodds of essential antipsychotic use were lower in low-income individuals than thosewith higher incomes. Odds of exposure to potentially inappropriate antipsychotic use,on the other hand, were higher among low-income individuals and seniors in long-termcare.Conclusion: There is evidence of persistent disparities in the use of antipsychoticmedication. Periodic examination and studies that identify causal factors and effectiveinterventions are needed to reduce disparities.

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Background – There is little evidence on the patterns of prescription drug use during pregnancyin Canada. To address this knowledge gap, the primary objectives of this thesis were to: 1)systematically review published antenatal drug utilization studies, and 2) provide the firstCanadian evidence on prescription drug utilization across the pregnancy period, overall, bytherapeutic category and fetal risk classification, in the province of British Columbia (BC). Methods - This thesis is comprised of two original studies. The first, a systematic review of antenatal drug utilization studies, was conducted according to an a priori protocol and included a double independent review process for the selection of articles and data abstraction. The second, a population-based empirical study in BC, was based on pharmacy claims records linked tomaternal hospital records. The period of pregnancy was constructed from the recorded gestational age and prescriptions filled before, during, and after this period were analyzed. Drugs were classified according to the World Health Organization Anatomical Therapeutic Classification System and US Food and Drug Administration risk categories indicating potential for fetal harm (categories D and X).Results – Published drug utilization studies reveal wide variation in estimates of overallprescription drug use in pregnancy (27% to 93% excluding vitamins and minerals). However,estimates are difficult to compare due to differences in methodology, data sources, classificationof prescription medicines, and inadequate reporting. In BC, the majority of pregnant women(63%) filled at least one prescription in pregnancy and approximately 1 in 12 filled a prescription for a drug with potential risks (category D or X). The most commonly used medicines were antiinfectives, doxylamine, dermatologicals, and drugs acting on the nervous system.Conclusion - A methodological framework and template for reporting exposures in pregnancyshould be developed to improve the quality and comparability of antenatal drug utilizationstudies. Evaluation of medicines with unknown risks that are commonly used in pregnancyshould be a priority for pharmacoepidemiological research. The use of drugs with potential risksshould be targeted by programs to improve appropriate prescribing in pregnancy.

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