Opioid agonist therapy discontinuation in British Columbia : a cross-sectional study of people who access harm reduction services

Background: The opioid overdose crisis has been contributing to increasing mortality rates in North America, with 2236 deaths in 2021 compared to 1768 in 2020, in British Columbia (BC) alone. Research has shown significant reductions in opioid overdose mortality rates among those who receive opioid agonist therapy (OAT), while OAT discontinuation has also been recognized as a period of high risk for overdose. This study assesses a provincial sample of individuals who use substances and access harm reduction supply distribution sites, with the objective to investigate the prevalence and correlates of OAT discontinuation across BC. Methods: This study utilizes data from the cross-sectional provincial-level Harm Reduction Client Survey (HRCS) administered in 2019, among individuals who use substances and are aged 19+. The outcome of OAT discontinuation included 2 levels: individuals who did and did not indicate discontinuing OAT in the past 6 months. Prevalence of potential correlates and their association with the OAT discontinuation outcome was assessed using Chi-squared or Fisher’s Exact test. Bivariate and multivariable analyses using logistic regression models examined associations between potential demographic, socioeconomic, accessibility, drug use and harm reduction correlates with the outcome. Results: Among the 194 participants included in the sample, 59.8% identified as cis man, 37.6% identified as indigenous and 38.1% were between the ages of 30-39 years old. Multivariable logistic regression analyses identified that: being aged ≥50 and taking the survey in medium/large urban areas was associated with lower odds of OAT discontinuation, while having experienced an overdose in the past 6 months was associated with greater odds of OAT discontinuation. Substance use, including opioids and stimulants, was similar among those who continued and discontinued OAT. Conclusion: Prevention of OAT discontinuation among individuals using substances in BC should address disparities in healthcare accessibility in remote and rural areas, while targeting younger individuals who have a history of overdose or are at higher risk of overdose, following OAT discontinuation. Equitable and continued access to harm reduction services can allow for safe consumption of various substances, that may continue among individuals enrolled in OAT programs.Medicine, Faculty ofPopulation and Public Health (SPPH), School ofGraduat