Comparison of self-reported substance use with biological testing among treatment-seeking patients with opioid use disorder.

Abstract Background Several factors may influence the validity of self-report. In this study, we aimed to assess the validity of self-reported drug use compared to urine testing among treatment-seeking patients with opioid use disorder (OUD). Methods This cross-sectional study recruited 293 patients with OUD, referred to the Iranian National Center for Addiction Studies (INCAS) clinic, from November 2015 to June 2017. The study compared self-reported opioid use in the past 72 h with the results of urinalysis, using immunoassay technique. We estimated sensitivity, negative predictive value, percent agreement, positive percent agreement, and Cohen's kappa statistics for those with OUD. Results The sensitivity of self-reported opioid use was 85.9%. Percent agreement, positive percent agreement, and Cohen's Kappa statistics between self-reported opioid use and urine testing for morphine in the first month were 88.5%, 78.1%, and 77.0, respectively. Multilevel logistic regression showed that longer treatment duration (OR = 1.21, 95%CI: 1.07–1.37, p-value = 0.002) was significantly associated with the agreement of self-reported opioid use with urine testing. Conclusion Self-report can be used as a reliable method for monitoring treatment adherence combined with random urine tests.