Comparison of Polydrug Use Prevalences and Typologies between Men Who Have Sex with Men and General Population Men, in Madrid and Barcelona.

This study compares the prevalence of drug use and the typologies of polydrug use (PDU) in men who have sex with men (MSM) and general population men (GPM). Participants were men aged 16-64, living in the provinces of Madrid and Barcelona: 1720 were recruited in a GPM survey, and 2658 were HIV-negative MSM from HIV/STIs diagnosis services. Lifetime and last-year prevalence of drug use and prevalence ratios (PRs) of MSM to GPM for the different drugs were calculated using Poisson regression. Latent class analysis (LCA) was performed to identify typologies of PDU. Lifetime use of the drugs considered was higher in MSM, and even higher for drug use in the last-year: PRs for cannabis, hallucinogens and cocaine ranged from 2-5; for amphetamine, ecstasy and methamphetamine 12-16; and above 60 for ketamine, GHB/GBL, inhalants and mephedrone. In the LCA for lifetime PDU four classes arose from the GPM (No-PDU (79.6%); Conventional PDU (13.8%); Intensive conventional PDU (4.9%); Heavy PDU (1.8%)) and four among MSM (No-PDU (57.7%); Conventional PDU plus poppers (18.8%); PDU preferring chemsex drugs (6.4%); Heavy PDU (17.2%)). For PDU during the last-year, three classes arose in the GPM: No-PDU (94.7%); Conventional PDU (4.3%); Heavy PDU (0.9%). For MSM, we identified four classes: No-PDU (64.7%); Conventional PDU plus poppers (15.6%); PDU preferring chemsex drugs (6.2%); Heavy PDU (13.5%). MSM should be considered a priority group for the prevention of the use of all drugs but the heterogeneity of PDU typologies regarding users' preference towards conventional and/or sexualised drugs needs to be taken into account.