Chemsex and rising substance use linked to sexually transmitted infections among men who have sex with men living with HIV in Bangkok, Thailand.

Objectives: We report longitudinal trends in alcohol and recreational drug use, and their associations with sexual behaviors and clinical outcomes in a Thai cohort of predominantly men who have sex with men (MSM) living with HIV.

Methods: From 2017 to 2019, participants in the RV254/SEARCH010 acute HIV cohort answered questions every 24 weeks about drug use and sexual behaviors. Longitudinal trends were assessed using the χ2 test for trend. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for factors potentially associated with recreational drug and alcohol use.

Results: Among 604 participants, the median age was 26 (interquartile range 23-31) years, and 93.5% were MSM. Alcohol consumption was reported in 83.3% and recreational drug use in 46.9% during the study period, with rising trends in both over the years. Participants who reported recreational drug use were more likely to have hepatitis C (OR 3.42, 95% CI 1.88-6.21), syphilis (OR 2.69, 1.75-4.13), gonorrhea (OR 7.74, 5.04-11.89), and chlamydia (OR 1.61, 1.12-2.31), and to engage in group sex (OR 7.74, 5.04-11.89). Participants who used any recreational drugs had more frequent viral blips (23.1% vs 14.2%, = 0.007) and reported missed doses of antiretroviral drugs more often (52.4% vs 36.9%, <0.001), but had no significant difference in viral suppression (94.1% vs 97.4%, = 0.06).

Conclusions: Among MSM living with HIV in Bangkok, recreational drug use has increased in recent years and was associated with hepatitis C and sexually transmitted infections, especially among men who participate in group sex. Prevention strategies and other interventions may improve treatment adherence and other HIV outcomes.