Background/introduction
The sexualised use of recreational drugs (Mephedrone, GBL/GHB, Crystal Meth) is thought to be associated with STI acquisition however there is little data showing a direct relationship. 

Methods
We reviewed 130 cases of MSM with an STI attending our STI service and 130 controls (MSM attending the STI service who did not have an STI) between 5th May 2015 and 2nd Nov 2015 (6 months). We collected demographic data, sexual behaviour, drug use and STI diagnoses.

Results
In the 6-month period there were 5,013 appointments with MSM. Reported condom-less anal sex was significantly higher in cases 90/121(74%) compared with controls 65/122(53%); (X2 = 11.71, p<0.005, OR 2.54). HIV prevalence was significantly higher in those with STIs: 71/130(55%) compared to those without STIs 33/130(25%); (X2 = 23.14, p<0.001, OR 3.53). Recreational drug use in the cases 38/122(31%) was significantly greater than in controls 20/125(16%); (X2 = 7.88, p<0.005, OR 2.37). In total Mephedrone was the most commonly used drug, followed by GBL/GHB. 

Discussion/conclusion
This data demonstrates a clear correlation between STI acquisition and recreational drug use in Men who have sex with men. Interventions to reduce party drug use should be implemented on an individual, local and national level to improve the sexual health of MSM, including reducing risk-taking behaviours.

Men who have sex with men, who are diagnosed with a sexually transmitted infection, report significantly more chem-sex: a case control study.