Rates of opioid agonist treatment prescribing in provincial prisons in Ontario, Canada, 2015–2018: a repeated cross-sectional analysis

OBJECTIVE: To describe opioid agonist treatment prescribing rates in provincial prisons and compare with community prescribing rates. DESIGN: We used quarterly, cross-sectional data on the number and proportion of people prescribed opioid agonist treatment in prison populations. Trends were compared with Ontario surveillance data from prescribers, reported on a monthly basis. SETTING: Provincial prisons and general population in Ontario, Canada between 2015 and 2018. PARTICIPANTS: Adults incarcerated in provincial prisons and people ages 15 years and older in Ontario. MAIN OUTCOMES AND MEASURES: Opioid agonist treatment prescribing prevalence, defined as treatment with methadone or buprenorphine/naloxone. RESULTS: In prison, 6.9%-8.4% of people were prescribed methadone; 0.8% to 4.8% buprenorphine/naloxone; and 8.2% to 13.2% either treatment over the study period. Between 2015 and 2018, methadone prescribing prevalence did not substantially change in prisons or in the general population. The prevalence rate of buprenorphine/naloxone prescribing increased in prisons by 1.70 times per year (95% CI 1.47 to 1.96), which was significantly higher than the increase in community prescribing: 1.20 (95% CI 1.19 to 1.21). Buprenorphine/naloxone prescribing prevalence was significantly different across prisons. CONCLUSIONS: The increase in opioid agonist treatment prescribing between 2015 and 2018 in provincial prisons shows that efforts to scale up access to treatment in the context of the opioid overdose crisis have included people who experience incarceration in Ontario. Further work is needed to understand unmet need for treatment and treatment impacts.