Abstract
INTRODUCTION: The global rise of concurrent use of opioids and methamphetamine presents challenges to stable methadone maintenance treatment (MMT). We assessed non-adherence to treatment and concurrent opioid use, along with associated factors, among people on MMT using methamphetamine in Vietnam. METHODS: This analysis utilized baseline data from a randomized clinical trial designed to investigate the effectiveness of various combinations of behavioral evidence-based interventions for methamphetamine use among patients on MMT in Vietnam (STAR-OM R01DA050486). We used data from 498 participants on MMT who self-reported using methamphetamine in the past 30 days and had been in MMT treatment for at least three months. The study determined adherence to MMT through medical record review and assessed concurrent opioid use via urine testing and documented test results in medical records. RESULTS: Within the last three months, 145 (29.1 %) did not adhere to MMT, and 212 (42.6 %) concurrently used opioids. Non-adherence to MMT were strongly associated with living at a considerable distance from the clinic (aOR = 1.80, 95 % CI: 1.10-2.90), being HIV positive (aOR = 0.51, 95 % CI: 0.27-0.97), and were marginally associated with using methamphetamine to reduce emotional distress (aOR = 1.56, 95 % CI: 0.99-2.45). Concurrent opioid use was associated with receiving treatment at clinics established during the scale-up period (aOR = 1.80, 95 % CI: 1.13-2.87), an extended duration of treatment at current clinics (aOR = 0.98, 95 % CI: 0.97-0.99), male gender (aOR = 2.09, 95 % CI: 1.05-4.13), and ever injecting methamphetamine (aOR = 1.98, 95 % CI: 1.13-3.46), besides MMT non-adherence (aOR = 2.71, 95 % CI: 1.72-4.29). CONCLUSION: Non-adherence to MMT and concurrent opioid use are prevalent among methamphetamine-using patients on methadone in Vietnam. Alongside well-documented factors influencing methadone program, the rise in methamphetamine adds further complexity to these challenges. Future intervention strategies must address both the underlying issues and methamphetamine use behaviors to effectively improve treatment outcomes. TRIAL REGISTRATION: NCT04706624. Registered 13 January 2021. https://clinicaltrials.gov/ct2/show/NCT04706624.