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.
Keywords: Addiction; Agreement; Congruence; Substance use.
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