Sexually transmitted infection testing and rates in men who have sex with men (MSM) using HIV pre-exposure prophylaxis.

Abstract

Rates of sexually transmitted infections (STIs) in men who have sex with men (MSM) have increased, particularly in MSM using HIV pre-exposure prophylaxis (PrEP) 1. Possible reasons for this may include increased condom-less anal sex, increased numbers of sexual partners and increased recreational drug use including chem-sex. Locally, we have a large MSM population and high rates of STIs. Using our clinic database, we identified HIV-negative MSM accessing our weekly dedicated MSM STI clinic over a 12-month period (1 October 2017 to 30 September 2018) and divided them into MSM coded as using PrEP and MSM not coded as using PrEP. A total of 565 patients had complete data for analysis, 289 MSM using PrEP and 276 not using PrEP. MSM using PrEP attended for 1069 STI tests and MSM not using PrEP attended for 709 STI tests in the time period (χ2 = 145; P < 0.0001). We found 173 cases of chlamydia, 107 in MSM using PrEP and 66 in MSM not using PrEP (P = 0.0008); 256 cases of gonorrhoea, 155 in MSM using PrEP and 101 in MSM not using PrEP (P = 0.0001); and 35 cases of infectious syphilis (STS), 24 in MSM using PrEP and 11 in MSM not using PrEP (P = 0.0371). Rectal infections were seen in significantly more MSM using PrEP (Table 1). MSM using PrEP attended more frequently for STI tests and had significantly higher rates of chlamydia, gonorrhoea (particularly rectal chlamydia and gonorrhoea) and infectious syphilis, in keeping with other published data 1. MSM using PrEP are a self-selected group (PrEP is not freely available in England currently), acquiring PrEP via clinical trials or buying generic tenofovir-emtricitabine online. They attend for STI testing and PrEP monitoring frequently (the recommendation is every 3 months) and are likely to be at higher risk of STIs than MSM choosing not to use PrEP. We believe that the MSM in this cohort were using PrEP because they self-identified as being at high risk of bacterial STIs; that is, using PrEP did not change their risk, similar to other published data and discussions 2. These data support their ongoing need to use PrEP, undergo regular STI testing and receive educational support for other strategies to reduce STI risk, including condom use.