Characterizing Drug use Typologies and Their Association with Sexual Risk Behaviors: A Latent Class Analysis Among Men who have Sex with Men in Mexico

Introduction Drug use behaviors are closely associated with increased risk for HIV and other STIs among men who have sex with men (MSM) globally. Less is known about the drug use characteristics and their association with HIV/STI risk among MSM in Mexico, who have 13 times higher risk of acquiring HIV than the general population. We characterized distinct classes of drug use behaviors among a nationwide sample of MSM in Mexico and tested their associations with HIV risk behaviors. Methods We used latent class analysis (LCA) to analyze injection/non-injection drug use data collected by the online Encuesta de Sexo Entre Hombres self-administered survey among 15,875 MSM living in Mexico between May-June 2017. MSM were recruited on general social media sites (e.g. Facebook and Twitter), popular LGBT+focused web pages (e.g. Soy Homosensual and Desastre), and dating apps (e.g. Grindr and Hornet). We used robust Poisson regression to examine associations between drug use classes and recent sexual risk behaviors while adjusting for sociodemographic characteristics. Results Most participants were under 30 years of age (65.5%), received a Bachelor's degree or higher (65.2%), gay-identified (82.5%), HIV negative (58.1%), and lived in the Mexico City/State of Mexico region (34.5%). We identified five distinct drug use classes: Limited Drug Use (75.4%), Marijuana Only (15.1%), Sex Event Popper+Marijuana (4.3%), Club Drug+Marijuana (4.2%), and Elevated Polydrug Use (1.0%). Compared to the Limited Drug Use class, participants in all other drug use classes were significantly more likely to engage in condomless anal intercourse (aPR=1.14-1.39; p<0.001), sex exchange (aPR=1.37-4.99; p<0.001), anonymous sex (aPR=1.22-2.01; p<0.001), group sex (aPR=1.50-3.28; p<0.001), and report an STI diagnosis in the past 12 months (aPR=1.24-2.20; p<0.002). Estimates were largest among the Elevated Polydrug Use class. Conclusions This study is the first to characterize drug use behaviors and HIV/STI risk among a national sample of MSM in Mexico. Understanding how distinct combinations of drug use behaviors impact sexual risk and prevention behaviors among MSM can inform how best to target and tailor future interventions to reduce HIV/STI incidence.