ABSTRACT:
The practice of chemsex, defined as the use of psychoactive substances in sexual contexts, has been associated with increased risk of HIV and other sexually transmitted infections (STIs). This study aimed to evaluate the global prevalence of chemsex among LGBTQIA+ populations. A systematic review and meta-analysis were conducted following PRISMA guidelines, with a protocol registered in PROSPERO. Searches were performed in MEDLINE/PubMed, Embase, Web of Science, and LILACS databases, as well as in grey literature, with no restrictions on language or publication date. Studies estimating the prevalence of chemsex among LGBTQIA+ adults were included. Random-effects meta-analyses of proportions were performed. Forty-seven studies, involving 88,340 participants and published between 2017 and 2025, were included. The overall pooled prevalence of chemsex was 20.6% (95% CI: 16.7–24.8). Studies using the classical definition of chemsex reported a pooled prevalence of 19.2% (95% CI: 15.3–23.5), while those employing broader definitions showed a higher prevalence of 26.5% (95% CI: 15.0–39.8). Sensitivity and leave-one-out analyses did not reveal substantial changes in the overall prevalence estimate. The pooled prevalence of sexualized drug use (SDU) was 26.8% (95% CI: 20.7–33.4), slamsex was 8.9% (95% CI: 4.0–15.4), and recreational drug use was 42.1% (95% CI: 30.6–54.0), all with high heterogeneity. In meta-regression analyses, publication year, specific LGBTQIA+ subpopulations studied, and methodological quality of the studies were associated with prevalence estimates. Chemsex demonstrates a high global prevalence among LGBTQIA+ populations, representing a significant risk context for HIV and other STIs. These findings highlight the need to integrate chemsex awareness into combination prevention strategies, incorporating harm reduction, mental health support, and approaches to address structural vulnerabilities.