Chemsex practices and pre-exposure prophylaxis (PrEP) trajectories among individuals consulting for PrEP at a large sexual health clinic in Montréal, Canada (2013-2020)
Bibliographic record
Abstract
INTRODUCTION: Chemsex among gay, bisexual and other men who have sex with men (gbMSM) has raised public health concerns because of its association with sexual behaviours that can increase transmission of sexually transmitted infections, including HIV. Pre-exposure prophylaxis (PrEP) is highly effective at blocking HIV acquisition, addressing important prevention needs among individuals practicing chemsex. This study aims to improve our understanding of chemsex practices and PrEP trajectories of gbMSM and transgender women consulting for PrEP. METHODS: We used data from the PrEP cohort of Clinique médicale l'Actuel, a major sexual health clinic in Montréal. We describe the sociodemographic profile of clients consulting for PrEP, characterize chemsex and polysubstance use trends over time, and evaluate PrEP trajectories using Kaplan-Meier curves. RESULTS: Among 2923 clients who consulted for PrEP between 2013-2020 (2910 cisgender gbMSM, 6 transgender gbMSM, 7 transgender women), 24 % reported chemsex in the past year and 13 % reported polysubstance use. The most common chemsex substances were ecstasy (14 %), GHB (13 %), and cocaine (12 %). The proportion of clients reporting chemsex and polysubstance use decreased over time. In both the chemsex and no-chemsex group, 73 % of clients initiated PrEP. The median time to discontinuation was similar between the chemsex (6.5 months; 95 %CI: 5.3-7.2) and no-chemsex group (6.9 months; 95 %CI: 6.3-7.5). CONCLUSION: Chemsex is not a barrier to PrEP initiation or persistence. However, these results suggest a high prevalence of chemsex among gbMSM consulting for PrEP, highlighting the need for services addressing the intersection of sexual health and substance use for this population.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".