Web-Based Harm Reduction Intervention for Chemsex in Men Who Have Sex With Men: Randomized Controlled Trial

Abstract

Background: Men who have sex with men (MSM) who practice chemsex have a higher likelihood of engaging in risky sexual behaviors and higher rates of HIV infection and other sexually transmitted infections (STIs) than those who do not. Objective: This trial aimed to evaluate the effectiveness of a web-based intervention in reducing the sexual harms of chemsex among MSM. Methods: The study was a 2-arm, assessor-blinded, randomized, parallel-group trial with a 3-month follow-up period. The study was conducted in the year 2021 in Hong Kong. Underpinned by the theory of planned behaviors and a harm reduction approach, the intervention consisted of interactive components and knowledge-based information about chemsex. Participants in the control group received brief information and content about sexual violence. The primary outcome was self-efficacy in refusing risky sexual behaviors and chemsex, as measured by the Condom Self-Efficacy Scale (CSES), Self-Efficacy for Sexual Safety (SESS) instrument, and Drug Avoidance Self-Efficacy Scale (DASES). The secondary outcomes included intentions to have chemsex, actual engagement in chemsex, HIV and other STI testing, and condom use in the last 3 months. All outcomes were self-reported. An online structured questionnaire was used to collect data. Results: In total, 316 MSM enrolled in the study. The intervention group demonstrated a significantly larger improvement in condom-use self-efficacy (as measured by CSES scores; time-by-group interaction: β=4.52, 95% CI 2.03-7.02; P