The development of an online risk calculator for the prediction of future syphilis among a high-risk cohort of men who have sex with men and transgender women in Lima, Peru.

Background Syphilis incidence worldwide has rebounded since 2000, particularly among men who have sex with men (MSM). A predictive model for syphilis infection may inform prevention counselling and use of chemoprophylaxis. METHODS: Data from a longitudinal cohort study of MSM and transgender women meeting high-risk criteria for syphilis who were followed quarterly for 2 years were analysed. Incidence was defined as a four-fold increase in rapid plasma reagin (RPR) titres or new RPR reactivity if two prior titres were non-reactive. Generalised estimating equations were used to calculate rate ratios (RR) and develop a predictive model for 70% of the dataset, which was then validated in the remaining 30%. An online risk calculator for the prediction of future syphilis was also developed. RESULTS: Among 361 participants, 22.0% were transgender women and 34.6% were HIV-infected at baseline. Syphilis incidence was 19.9 cases per 100-person years (95% confidence interval (CI) 16.3-24.3). HIV infection (RR 2.22; 95% CI 1.54-3.21) and history of syphilis infection (RR 2.23; 95% 1.62-3.64) were significantly associated with incident infection. The final predictive model for syphilis incidence in the next 3 months included HIV infection, history of syphilis, number of male sex partners and sex role for anal sex in the past 3 months, and had an area under the curve of 69%. The online syphilis risk calculator based on those results is available at: www.syphrisk.net. CONCLUSIONS: Using data from a longitudinal cohort study among a population at high risk for syphilis infection in Peru, we developed a predictive model and online risk calculator for future syphilis infection. The predictive model for future syphilis developed in this study has a moderate predictive accuracy and may serve as the foundation for future studies.

Sexual health knowledge and practices and STI/HIV prevalence among long-distance truck drivers in Peru.

OBJECTIVES: HIV and other sexually transmitted infections remain a challenge globally and many key groups have yet to be studied. Evidence shows that truck drivers may have high-risk behaviors and higher sexually transmitted infection/HIV prevalence because they are a highly mobile population. However, there is little to no information on this group in Peru. Therefore, we explored the sexual health knowledge and practices and carried out sexually transmitted infection/HIV testing among male truck drivers and their assistants in Peru. METHODS: We conducted a cross-sectional study utilizing cell phone-based behavioral surveys and sexually transmitted infection testing, including HIV, syphilis, gonorrhea, and chlamydia, with truck drivers and their assistants who were traveling on two major international highways in Peru. RESULTS: A total of 1150 truck drivers and assistants participated. Participants were middle-aged men (average age = 39.8 years), 96.0% had complete secondary education, 78.4% were in stable relationships, and 88.7% earned more than minimum wage. The majority were aware of sexually transmitted infections/HIV, but very few recognized sexually transmitted infection symptoms. Few participants (under 5%) reported recent sexually transmitted infection symptoms. Prevalence of sexually transmitted infections was also low: no one had gonorrhea; 0.1% had HIV; 0.4% had recent syphilis infection (rapid plasma reagin ≥1:8); and 2.0% had chlamydia. The prevalence of these diseases is not different from that of the general population in Peru. CONCLUSION: When compared to other truck drivers worldwide, Peruvian truck drivers appear to have a lower risk of HIV/sexually transmitted infections. This may be since Peruvian drivers are older, more educated, have higher income, and spend fewer days away from home than their peers globally.