Correlates of days of medication for opioid use disorder exposure among people living with HIV in Northern Vietnam

Background: In Vietnam, access to medications for opioid use disorder (MOUD) for people living with HIV has rapidly expanded, but MOUD use over time remains low. We sought to assess factors associated with days of MOUD treatment exposure. Methods: From 2015 to 2019, patients with OUD in six Northern Vietnamese HIV clinics were randomized to receive HIV clinic-based buprenorphine (BUP/NX) or referral for methadone maintenance therapy (MMT) and followed for 12 months. All MOUD doses were directly observed and abstracted from dosing logs. The primary outcome was days of MOUD treatment exposure (buprenorphine or methadone) received over 12 months. Negative binomial regression modelled associations with days of MOUD exposure. Results: Of 281 participants, 264 (94%) were eligible for analysis. Participants were primarily male (97%), unmarried (61%), employed (54%), and previously arrested (83%). Participants had a mean 187 (SD 150) days of MOUD exposure with 134 (51%) having at least 180 days, and 35 (13.2%) having at least 360 days of MOUD exposure. Age (IRR 1.26, 95% CI 1.02–1.55), income (IRR 0.96, 95% CI 0.93–1.001), and methadone (IRR 1.88, 95% CI 1.51–2.42) were associated with MOUD exposure in multivariate models. Multivariate models predicted 127 (95% CL 109–147) days of MOUD exposure for HIV clinic based-buprenorphine vs 243 (95% CL 205–288) for MMT. Conclusion: MOUD treatment exposure was suboptimal among patients with HIV and OUD in Northern Vietnam and was influenced by several factors. Interventions to support populations at risk of lower MOUD exposure as well programs administering MOUD should be considered in countries seeking to expand access to MOUD.