Evaluating employment and treatment outcomes in adults with opioid use disorder initiating opioid agonist therapy in a pan-Canadian pragmatic randomized clinical trial

Background: As a key social determinant of health among individuals with opioid use disorder (OUD), characterizing employment patterns is critical for understanding the socioeconomic and clinical context in which individuals engage in treatment. Additionally, the relationship between employment and treatment outcomes in opioid agonist therapy (OAT) remains insufficiently understood. This thesis examined employment and its impact on treatment outcomes among individuals with non-heroin, prescription-type OUD initiating OAT within a pan-Canadian randomized trial. Methods: We conducted secondary analyses using data from a multicentre pragmatic randomized controlled trial conducted across Canada between 2017 and 2020 comparing methadone and buprenorphine/naloxone treatment for OUD. First, a cross-sectional analysis of baseline data was performed to identify factors associated with employment using multivariable logistic regression. Second, we evaluated the association between employment status and OAT discontinuation among participants initiating treatment using Cox proportional hazards models and Kaplan–Meier survival analyses. Results: Among randomized participants (n = 267), 87 (32.6%) reported employment in the 30 days prior to baseline. Self-reported heroin use (adjusted odds ratio [AOR] 2.15, 95% CI 1.03–4.53) and British Columbian residency (AOR 3.58, 95% CI 1.44–9.42) were positively associated with employment. Among participants initiating OAT (n = 206), though employment was not independently associated with time in treatment, a significant interaction between employment and treatment type was observed in both assigned (p = 0.018) and any OAT (p = 0.017) discontinuation. Specifically, among participants randomized to buprenorphine/naloxone, employed individuals had significantly lower risk of discontinuation than non-employed individuals (adjusted hazard ratio [AHR] 0.50, 95% CI 0.26–0.99 for any OAT discontinuation). Among participants randomized to methadone, no significant difference was observed. Conclusion: Employment was relatively uncommon among individuals initiating OAT and was associated with province of residence and self-reported heroin use. Although employment was not independently associated with treatment discontinuation, retention patterns differed by treatment delivery models between employed and non-employed groups. These findings highlight the complex role of employment in treatment-seeking OUD populations and importance of considering social determinants, like employment, when interpreting clinical trial findings and their potential role in affecting treatment outcomes.