Validation of the alcohol, smoking and substance involvement screening test (ASSIST) for identifying methamphetamine use among people on methadone maintenance treatment in Vietnam

Abstract Background and Aims Identifying those who use methamphetamine or are at high risk of using methamphetamine is essential so that early, appropriate intervention can be made. This study evaluated the use of the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) for identifying methamphetamine use among people on methadone maintenance treatment (MMT) in Vietnam. Methods From June 2021 to May 2023, all people on MMT at 15 methadone clinics in Hanoi and Ho Chi Minh City, Vietnam, were invited to participate in this study. Participants underwent a face‐to‐face interview to complete the 8‐item ASSIST. Participants also had a urine drug test (UDT) for methamphetamine use. Discriminant properties of the ASSIST were evaluated using UDT as the reference. Results Among 6709 participants, 10.7% ( n  = 717) tested positive for methamphetamine use via UDT. The ASSIST demonstrated robust discriminant abilities to identify those who used methamphetamine [area under the curve (AUC) = 0.872; 95% confidence interval (CI) = 0.856–0.887]. At the commonly used cutoff of 4, the ASSIST had a sensitivity of 83.8% and a specificity of 82.0%. At this cutoff, 82.2% of the ASSIST results aligned with UDT outcomes (kappa coefficient = 0.41, P  < 0.001) and the ASSIST identified a prevalence of 25.0%. At higher cutoffs, the sensitivity of the ASSIST decreased but both the specificity and the agreement with the UDT results increased. Conclusions The Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) appears to be reliable and valid in identifying methamphetamine use among people on methadone treatment in Vietnam. Cutoff adjustments may help to reduce false positive rates.