Objective: In this study, we evaluated the concordance between urine drug screening (UDS) and self-reported use in a pragmatic randomized clinical trial.

Methods: Our data was drawn from OPTIMA, a 24-week pragmatic multicentric open-label randomized-controlled trial comparing flexible take-home dosing of buprenorphine/naloxone to the methadone standard model of care for treating prescription-type opioid use disorder. A total of 272 participants were randomized (1:1 ratio) to methadone or buprenorphine/naloxone. Following treatment initiation, participants were followed-up every 2 weeks for 24 weeks. During each visit, participants provided urine samples for UDS and self-reported their substance use over the past 2 weeks. Self-reported use was dichotomized to align with UDS detection windows. Tetrachoric correlations and 2 × 2 contingency tables were used to estimate the sensitivity, specificity, positive predictive value and negative predictive value of self-reported use. A generalized linear mixed model assessed how substance type, time in the study, treatment assignment, study site, unstable housing, and sex impacted self-report accuracy.

Results: Significant differences were found between substance types ( < 0.001) and study sites ( < 0.001). Fentanyl, cannabis, and amphetamines consistently showed the greatest concordance between measurement methods. Hydromorphone, oxycodone, heroin, and benzodiazepines had low sensitivity and low positive predictive value. Participants from Québec showed higher concordance between UDS and self-reported use compared to those from British Columbia, Alberta, and Ontario. There was no moderating effect of treatment assignment ( = 0.174), time in the study ( = 0.221), unstable housing ( = 0.733), or sex ( = 0.321) on the concordance between UDS and self-reported use.

Conclusions: Our results indicate that concordance between UDS and self-reported use is impacted by several factors. Combining UDS and self-reported use could help provide a more accurate assessment of substance use.