P1-S5.13 Recreational drug use during sex is associated with STI among clients of a large STI outpatient clinic in Amsterdam, The Netherlands

Background Previous studies have shown that recreational drug use is associated with high-risk sexual behaviour and STI. Little is known about the relationship between the use of specific recreational drugs during sex, sexual behaviour and the risk for any STI (chlamydia (CT), gonorrhoea (NG) and/or syphilis) or the three STI separately in heterosexual men, men having sex with men (MSM) and women. We assessed the prevalence of recreational drug use during sex, and assocations of drug use during sex with high-risk sexual behaviour and STI. Methods Attendees of the STI clinic of the Public Health Service of Amsterdam were interviewed during three waves of a bi-annual anonymous survey (2008–2009) about sexual behaviour in the preceding 6 months (number of steady and casual sex partners, condom use during vaginal or anal sex) and specific recreational drug use just before or during sex in the preceding 6 months (cannabis, XTC, poppers, heroine, cocaine, GHB, apomorfine, amphetamine, methylamphetamine, mushrooms, ketamine and explosion). Participants were tested for CT, NG and syphilis. Associations between drug use during sex and high-risk sexual behaviour and STI were analysed using multivariable logistic regression analyses. Analyses were done separately for heterosexual men, men who have sex with men (MSM) and women. Results In total, 1012 heterosexual men, 749 MSM and 1254 women participated in this study. Of these, 11.7% had CT, 3.5% NG and 1.4% syphilis. Recreational drug use during sex in the previous 6 months was reported by 22.5% of heterosexual men, 52.7% of MSM and 15.6% of women. In all three groups, drug use during sex was associated with unprotected vaginal and anal sex and more casual sex partners. In multivariable analyses among MSM, adjusting for age, ethnicity, educational level and sexual behaviour, poppers use was associated with any STI (adjOR 1.8, 95% CI 1.2 to 2.6) and with NG (adjOR 2.6, 95% CI 1.6 to 4.2), and GHB use with syphilis (adjOR 2.3, 95% CI 1.0 to 5.0). In multivariable analyses among women, GHB use was associated with any STI (adjOR 4.7, 95% CI 1.8 to 12.2) and CT (adjOR 3.5, 95% CI 1.1 to 11.4). In heterosexual men, drug use during sex was not associated with STI. Conclusions STI clinic clients frequently report recreational drug use during sex and this is associated with high-risk sexual behaviour in heterosexual men, MSM and women. The use of drugs during sex is associated with STI in MSM and women, but not in heterosexual men.