Sex, drugs, and sexually transmitted infections: a cluster analysis among men who have sex with men in Amsterdam and surrounding urban regions, the Netherlands

International audienceBackgroundMen who have sex with men (MSM) are at high risk for sexually transmitted infections (STI) and often have sex while under the influence of drugs (sexualized drug use). We aimed to identify classes of MSM in Amsterdam and in surrounding urban regions with distinctive patterns of sexualized drug use and their association with STI.MethodsIn this cross-sectional study, data on MSM were collected at STI clinics in the Netherlands between September-December 2017. Information on drug use, sociodemographics and sexual risk behavior, including lab-confirmed STI (chlamydia, gonorrhea, syphilis and HIV) was collected and compared between Amsterdam and surrounding urban regions. Latent class analysis was used to identify classes with similar drug use patterns, which were then linked to sexual behavior and STI.ResultsWe included 4461 MSM who were a median 35 years old (IQR = 27–47) and mostly Dutch (56.9 %). Use of all drugs was more often reported in Amsterdam compared to surrounding regions (p