HIV treatment optimism and crystal methamphetamine use and initiation among HIV-negative men who have sex with men in Vancouver, Canada: A longitudinal analysis

Background: Treatment as Prevention (TasP) leading to increased HIV treatment optimism among men who have sex with men (MSM) has been previously associated with behavioural risk compensation, though not yet via crystal methamphetamine (CM) use. Among HIV-negative MSM in a TasP environment, this study aimed to investigate the prevalence of recent CM use over time, examine the association between HIV treatment optimism and CM use and initiation, and identify correlates of recent CM use and predictors of CM initiation.

Methods: Using data from a prospective behavioural cohort study of sexually active MSM in the Vancouver area, we used multi-level generalized mixed effect models to evaluate temporal trends in CM use, univariable and multivariable logistic regression to identify covariates of recent CM use, and univariable and multivariable survival analysis to identify predictors of CM initiation.

Results: Of 497 HIV-negative cohort participants, 10.3% reported any recent CM use at enrollment. From 2012-2016, there were no statistically significant temporal trends in overall CM use or with routes of administration. In multivariable logistic regression analyses, HIV treatment optimism was not associated with recent CM use (not retained in final model) or CM initiation (aHR = 1.06, 95% CI:0.98-1.15). Significant correlates of CM use include recent gamma-hydroxybutyrate (GHB) and ecstasy use, and having received/given drugs for sex.

Conclusions: Among HIV-negative MSM in Vancouver, HIV treatment optimism does not appear to be independently associated with CM use or initiation of use, though use of CM was both prevalent and stable over time.