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

Abstract

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.

Keywords: Chemsex; HIV; MSM; Meta-analysis; Substance use; Transactional sex.

Figure 1.

PRISMA Flow diagram of the study selection process.

Figure 2.. Forest plot of the chemsex associated substances prevalence among MSM with classic frequentist approach.

Note. Cocaine: Heterogeneity: Q=24.04, df=5, p=0.0002, I²=93.16%; GHB/GBL: Heterogeneity: Q=312.29, df=5, p<0.0001, I²=99.73%; Ketamine: Heterogeneity: Q=193.84, df=7, p<0.0001, I²=96.29%; Methamphetamine: Heterogeneity: Q=665.30, df=14, p<0.0001, I²=99.66%. 95%CI=95% confident interval.

Figure 3.. Forest plot of the chemsex activity prevalence among different MSM population with classic frequentist approach.

Note. MSM general: Heterogeneity: Q=1218.51, df=13, p<0.0001, I²=98.70%; MSM sex work clients: Heterogeneity: Q=156.91, df=3, p<0.0001, I²=98.30%; MSM sex workers: Heterogeneity: Q=35.22, df=2, p<0.0001, I²=91.58%. 95%CI=95% confident interval.

Figure 4.. Forest plot of the association of MSM living with HIV in comparison to MSM living without HIV in chemsex activity computed with classic frequentist approach.

Note. Heterogeneity: Q=225.31, df=7, p<0.0001, I²=96.68%. 95%CI=95% confident interval.

Figure 5.. Forest plot of the association of MSM living with HIV in comparison to MSM living without HIV in chemsex activity computed with Bayesian approach with half normal distribution prior (scale of 0.5).

Note. 95% CrI = 95% credible interval. The black line indicates the quoted estimates specified through effect from individual study and its σi as same as in the frequentist approach. The grey line presents the shrinkage intervals which illustrate the posterior of each studyʼs true effect. The black diamond presents the posterior distribution of the pooled effect while the black bar shows the prediction distribution. The scale on the x-axis is log odds ratio.