JMIR Publications

ABSTRACT

Background:

Men who have sex with men (MSM) who practise chemsex have higher rates of engaging risky sexual behaviours, and human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs) than those who do not.

Objective:

This trial aimed to evaluate the effectiveness of an internet-based intervention in reducing the sexual harms of chemsex among MSM.

Methods:

The study was a two-armed, assessor-masked, randomised, parallel-group trial with a three-month follow-up period. Underpinned by the theory of planned behaviours and harm reduction approach, the intervention consisted of interactive components and knowledge-based information about chemsex. The primary outcome was self-efficacy in refusing risky sexual behaviours and chemsex, as measured by the Condom Self-Efficacy Scale (CSES), the Self-Efficacy for Sexual Safety (SESS) instrument and the Drug Avoidance Self-Efficacy Scale (DASES). The secondary outcomes included an intention to have chemsex, actual engagement in chemsex, HIV and other STI testing and condom use.

Results:

In total, 316 MSM enrolled in the study. The intervention group demonstrated significantly better improvement in the primary outcome as measured by the CSES (time-by-group interaction: β, 4.52 [95% CI, 2.03–7.02]), SESS (time-by-group interaction: β, 2.11 [95% CI, 0.66–3.56]) and DASES (time-by-group interaction: β, 6.98 [95% CI, 1.75–12.22]) than the control group. Participants in the intervention group had significantly greater reduction in the likelihood to have engaged in chemsex (time-by-group interaction: aOR, 0.23 [95% CI, 0.10–0.53]) or an intention to have chemsex in the previous three months (time-by-group interaction: aOR, 0.37 [95% CI, 0.18–0.78]) than the control group. Participants in the intervention group had significantly better improvement in the likelihood to have received HIV testing (time-by-group interaction: aOR, 3.08 [95% CI, 1.72–5.54]) than the control group.

Conclusions:

The current study provides empirical evidence for governments, health authorities and other stakeholders to put more resources into delivering chemsex-preventive intervention using online platforms. Clinical Trial: International standard randomized controlled trial number (ISRCTN) registry: ISRCTN20134522 registered on 17 March 2021.