Asymptomatic anal sexually transmitted infections in HIV-positive men attending anal cancer screening

Background HIV-positive men who have sex with men (HIV+ MSM) have an increased risk for anal dysplasia and for sexually transmitted infections (STIs). Objectives We determined the positivity rates of Chlamydia trachomatis (CT), Neisseria gonorrhoea (NG), Mycoplasma genitalium (MG) and syphilis in HIV+ MSM participating in an anal cancer screening programme. Methods In total, 852 intra-anal swabs were collected from 503 HIV+ MSM between 2012 and 2014. Anal cytology and polymerase chain reaction assays for human papillomavirus (HPV), CT, NG and MG detection were performed. The syphilis status was determined serologically. Risk factors for STIs were explored by multiple logistic regression analysis. Results In total 20.7% (104 of 503) of the patients had an STI other than HPV within the study period. The most common was CT, found in 10.9%, followed by NG (8.9%) and MG (4.2%). Early syphilis was detected in 4.6% and past syphilis in 44.5% of the HIV+ MSM. Eighteen patients (3.6%) had more than one STI episode, and 90.6% of the 127 cases of STIs were asymptomatic. Age, anal HPV infection, abnormal anal cytology and previous syphilis were risk factors for STI. Conclusions Anal STIs are frequent and mostly asymptomatic in HIV+ MSM participating in anal cancer screening. STI screening should be incorporated into anal cancer screening programmes for HIV+ MSM.