Sexually Transmitted Infections:associations in persons with HIV on treatment.

Established HIV-infection, when associated with other sexually transmissible infections (STI), interacts with them in a number of different ways. To investigate some of these associations, we established a sub-cohort of ten sexual health clinics within a much larger prospective longitudinal cohort of HIV-positive people mostly on antiretroviral treatment (ART), the Australian HIV Observational Database (AHOD). The clinics collected additional data on STI diagnoses and treatments.Preliminary analysis (2005-11) showed a high incidence of four STI, namely, infectious syphilis, chlamydia, gonorrhoea, and genital warts. These were the first measurements of STI incidence among persons being treated for HIV in Australia. Predictive factors for an STI diagnosis (2010-2013) included age less than 30 years and being MSM, (similar to other cohorts) . We also found a history of prior STI as a risk factor for future STI diagnosis. This had not previously been described in HIV-positive populations, although it is an intuitive finding. Risk factors assist targetting of health promotion efforts. Our study of individuals in AHOD (2010-2015) followed for over 2,000 person-years, included many thousands of viral load measurements. We found no elevation in viral loads before, during, or after episodes of four STI. Our findings add to a convincing body of data that point toward the reduction of viral load by ART having a greater effect on HIV transmission than STI and their treatment.Being diagnosed with an STI in the first 5 years of follow-up (2010-2015) was not a risk factor for later detectable viral loads, measured in the following 3 years (2015-2018). Therefore, it does not necessarily follow that extra vigilance is required in individuals with STI, with respect to HIV-management, to ensure long-term viral suppression.Finally, we investigated the feasibility of using treatment records as surrogate markers for infectious syphilis and gonorrhea, in populations where consistent diagnosis data may be problematic. Overall, the number of treatments in 2010-2015 exceeded the number of diagnoses by a small amount, and risk factors were generally similar. We recommend further exploration of this concept