Chemsex and chemsex associated substance use among men who have sex with men in Asia: A systematic review and meta-analysis

Background: The prevalence of chemsex has been reported by multiple systematic reviews among men who have sex with men (MSM) focussing predominantly on the Global North. An Asian perspective with meta-analytical evidence is missing. This meta-analysis summarised the prevalence of substance use associated with chemsex, and chemsex activity among MSM and MSM sub-populations in Asia, as well as the likelihood for chemsex among MSM living with or without HIV. Methods: We utilized PubMed, Web of Science and medRxiv to search for literature describing chemsex and its associated substance use among MSM and MSM sub-populations in Asia from January 1, 2010 to November 1, 2021 to conduct three meta-analyses with both frequentist and Bayesian approaches. Results: We identified 219 studies and included 23 in the meta-analysis. Based on the frequentist models, methamphetamine was the default substance associated with chemsex among MSM in Asia (prevalence = 0.16, 95 %CI:0.09–0.22), followed by GHB/GBL (prevalence = 0.15, 95 %CI:0.03–0.27) and ketamine (prevalence = 0.08, 95 %CI:0.04–0.12), but hardly any cocaine (prevalence = 0.01, 95 %CI:0.00–0.03). Compared to a general MSM population (prevalence = 0.19, 95 %CI:0.15–0.23), MSM engaging in transactional sex showed a higher prevalence of chemsex (MSM sex work clients [prevalence = 0.28, 95 %CI:0.11–0.45]; MSM sex worker [prevalence = 0.28, 95 %CI:0.17–0.26]). MSM living with HIV also showed higher odds of chemsex activity (OR = 3.35, 95 %CI:1.57–7.10), compared to MSM living without HIV. Both meta-analytic models converged, indicating robust evidence. Conclusions: Our meta-analyses showed that chemsex is not uncommon among MSM, and MSM engaging in transactional sex in Asia. We confirmed that MSM living with HIV have a higher likelihood of engaging in chemsex, too. Chemsex prevention and management strategies in Asia should be adjusted accordingly.