Long-Term Health Outcomes of People with HIV Engaged in Chemsex: A Prospective Cohort Study on Drug Use, Sexual Behaviour, Sexually-Transmitted Infections and Vulnerability.

INTRODUCTION

Chemsex, the intentional use of drugs to enhance sexual experiences among gay, bisexual, and other men who have sex with men (gbMSM), is linked to high-risk sexual behaviours and increased sexually transmitted infections (STIs). Data on its long-term evolution after implementing specific strategies in HIV settings are limited. We evaluated the incidence of drug use, sexual behaviour, STIs, and vulnerabilities over 3 years following a specific approach at the HIV Unit of Hospital Clinic in Barcelona, Spain.

METHODS

We included 209 gbMSM living with HIV who engaged in chemsex in a prospective cohort (2018-2022). Quarterly visits assessed sexual behaviours, drug use, and STIs screening. Data were collected via self-administered questionnaires, medical records, and microbiological tests. Statistical analyses included descriptive statistics and Poisson regression models.

RESULTS

Chemsex incidence decreased significantly (IRR 0.88, 95% CI 0.83-0.92, p < 0.001). People engaging in intravenous drug use (slamming) decreased in year 2 (IRR 0.71, 95% CI 0.52-0.98, p = 0.037) but rose non-significantly in year 3 (IRR 0.86, 95% CI 0.60-1.25, p = 0.434). High-risk sexual behaviours persisted, specifically unprotected anal sex (IRR 1.02, 95% CI 0.96-1.08, p = 0.481) and unprotected fisting (IRR 1.20, 95% CI 1.05-1.39, p = 0.010). Syphilis cases declined (IRR 0.40, 95% CI 0.26-0.60, p < 0.001). At baseline, 29% had HCV antibodies, with five new acute HCV cases. Concerns about chemsex decreased (IRR 0.52, 95% CI 0.43-0.63, p < 0.001), whereas the demand for sexuality-related assistance increased (IRR 1.53, 95% CI 1.20-1.94, p = 0.004). Loss to follow-up (21%) was greater among younger individuals, people engaging in intravenous drug use (slamming) (IRR 2.43 95% CI 1.33-4.42, p = 0.004), detectable HIV viral load (IRR 3.01, 95% CI 1.57-5.76, p = 0.001), and greater need for help (IRR 1.35, 95% CI 1.03-1.78, p = 0.03). Migrants and sex workers had higher rates of syphilis, lower education levels, and increased prevalence of STIs.

CONCLUSION

Chemsex incidence and syphilis rates declined, but persistent high-risk behaviours, subgroup vulnerabilities, and increasing demand for sexuality-related assistance require targeted interventions and comprehensive support.