Psychometric Characteristics of the Persian Version of the Opiate Dosage Adequacy Scale (ODAS)

INTRODUCTION: The opiate dosage adequacy scale (ODAS) is one of the most common assessment tools in studies on substance use disorders, which evaluates the “adequacy” of opiate medication doses in individuals recruited in maintenance approaches. There is no investigation on the Persian version of this questionnaire in Iran. This research validated a Persian version of the ODAS. METHODS: The Persian version of the ODAS was translated and revised based on the original scale presented by González-Saiz et al. The psychometric characteristics of the ODAS were assessed via direct interviews. Three trained interviewers questioned 250 patients treated in methadone maintenance clinics in Mazandaran Province (Northern Iran) for more than three months. Internal consistency and factor analysis were conducted using SPSS software, version 24. RESULTS: The internal consistency of ODAS was satisfactory (Cronbach’s α=0.81). Across all items, considerable inter-rater reliability was discovered (kappa values between 0.90 and 1). A four-component structure was produced by the factor analysis that accounted for 77.5% of the total variance. Cronbach’s α coefficients of the four components of Heroin craving and overmedication, Consumption, objective opiate withdrawal symptoms, and subjective opiate withdrawal symptoms were 0.84, 0.91, 0.83, and 0.74, respectively. CONCLUSION: The reliability and validity of the Persian version of the ODAS were satisfactory in a sample of methadone maintenance subjects. HIGHLIGHTS: The opiate dosage adequacy scale (ODAS) is a clinical tool for measuring the adequacy of methadone doses. The Persian version of ODAS has good validity, internal consistency, and inter-rater reliability; The Persian version of the ODAS, as a valid and reliable tool, can be used for the Iranian people under methadone maintenance. PLAIN LANGUAGE SUMMARY: In Iran, opioids are among the most common forms of illicit drugs. In opioid maintenance programs, the adequacy of methadone doses has an important effect on treatment outcomes. Clinicians typically assess the adequacy of doses based on the patient's response to the medication. Different tools are used in clinical studies to evaluate it. One of these tools is the ODAS, developed by González-Saiz et al. In the present study, we validated the Persian version of the ODAS for Iranian patients receiving methadone maintenance programs. The results confirmed the four-factor structure of the Persian ODAS and showed its good internal consistency and inter-rater reliability.