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

Objectives: This study evaluates the prevalence and correlates of opioid agonist therapy (OAT) discontinuation across British Columbia (BC), using a sample of individuals who used substances and accessed harm reduction sites.

Design: This study uses data from the 2019 cross-sectional Harm Reduction Client Survey (HRCS).

Setting: The 2019 survey was administered from October to December at 22 harm reduction supply distribution sites across the 5 Regional Health Authorities of BC.

Participants: The 2019 HRCS was administered among individuals who used illicit substances in the past 6 months and were aged 19 years and above.

Primary And Secondary Outcome Measures: The primary outcome was defined as self-reported discontinuation of OAT in the past 6 months. Measures of association (χ and Fisher's exact tests) and logistic regression models were used to assess the strength of association between OAT discontinuation and demographic, socioeconomic, accessibility, drug use and harm reduction correlates.

Results: Of the 194 participants included, 59.8% self-identified as cis man, 37.6% self-identified as Indigenous, 38.1% were aged 30-39 years and 43.8% had discontinued OAT in the past 6 months. Multivariable logistic regression analyses identified that those aged ≥50 years (AOR=0.12, 95% CI (0.03 to 0.45)) and those who took the survey in medium/large urban areas (AOR=0.27, 95% CI (0.07 to 0.98)) were significantly less likely to discontinue OAT, while those who experienced an overdose in the past 6 months were significantly more likely (AOR=3.77, 95% CI (1.57 to 9.03)) to have discontinued OAT in the past 6 months. Substance use, including opioids and stimulants, was similar among those who continued and discontinued OAT. Of the 73 participants who discontinued OAT and provided a reason, one-third reported discontinuing OAT because treatment was not effective, 27.4% could not get to the pharmacy during open hours, 23.3% could not make their clinic appointment and 15.1% reported challenges with transportation/travel.

Conclusions: OAT discontinuation prevention efforts for individuals using substances in BC need to address disparities in healthcare accessibility, especially in rural areas and among younger individuals. Continued access to harm reduction services can allow for safer consumption of substances for individuals enrolled in OAT programs.