Comparing characteristics and outcomes of different opioid agonist treatment modalities among opioid-dependent federal men correctional populations in Canada

Background: Limited evidence exists in Canada on outcomes related to Opioid Agonist Treatment (OAT) and/or differences between OAT modalities among persons in correctional institutions. This study addresses this knowledge gap by examining key characteristics and outcomes of men in Canadian federal correctional institutions across treatment modalities. Methods: A retrospective cohort of men incarcerated in federal correctional institutions (N = 2833) were classified into four groups - three OAT participant groups: prescribed methadone (M-OAT), prescribed buprenorphine/naloxone (Suboxone (R); S-OAT) and those who switched between the two OAT modalities at least once (X-OAT). The fourth group was a non-treatment comparison group (Non-OAT). Two-thirds of study participants were released and examined for post-release outcomes. Descriptive statistics and multi-variate Cox proportional hazards regression were used. Results: The X-OAT group was more likely than the other study groups to have positive urinalysis tests, disciplinary charges, or institutional security or behavioral incidents. Survival analysis indicated that the X-OAT had an adjusted hazard of a return to custody that was 57% greater than the other groups. Conclusions: This study indicates that individuals switching OAT modalities are a more complex group needing additional supports, especially for community reintegration. Although few of the returns to custody were due to new offences, a third of participants in the OAT groups had their release revoked, indicating a high need population mostly due to their substance use.