There is a high burden of sexually transmitted infections (STIs) among individuals who initiate or persistently use pre-exposure prophylaxis (PrEP), according to a study published in JAMA Network Open. However, there is an opportunity to leverage the global interest in PrEP programs to promote integrated STI services.
The investigators of this systematic review and meta-analysis sought to estimate the prevalence of STIs among patients initiating HIV PrEP therapies, including emtricitabine and tenofovir disoproxil fumarate, and the incidence of STIs reported during PrEP use.
The investigators searched relevant databases and identified 88 studies from 26 countries that reported the prevalence and/or incidence of STIs among patients using PrEP. Independent reviewers performed data extraction, and the Joanna Briggs Institute critical assessment tool was used to assess the studies’ methodologic quality. A random-effects meta-analysis was used to measure the pooled prevalence of baseline STIs (defined as STIs diagnosed within 3 months of initiating therapy) and the pooled incidence of STIs (defined as STI cases diagnosed while taking PrEP). Subgroup meta-analyses were based on predefined covariates, including anatomic site, study populations, and country income level.
The pooled prevalence of STIs among individuals prior to starting PrEP was 23.9% (95% CI, 18.6%-29.6%), calculated from studies reporting a composite outcome of chlamydia, gonorrhea, and early syphilis. Prevalence of STIs by anatomic site was highest in the anorectum (8.5% of chlamydia cases and 9.3% of gonorrhea cases) compared with genital sites (4.0% of chlamydia cases and 2.1% of gonorrhea cases) and oropharyngeal sites (2.4% of chlamydia cases and 4.9% of gonorrhea cases).
The pooled incidence of STIs, reported as the composite outcome of chlamydia, gonorrhea, and early syphilis, was 72.2 per 100 person-years (95% CI, 60.5-86.2 per 100 person-years). Incidence of STIs by anatomic site was also highest in the anorectum (29.9 vs 21.3 per 100 person-years for chlamydia and gonorrhea, respectively) compared with genital sites (10.4 per 100 person-years for chlamydia and 9.9 for gonorrhea per 100 person-years) and oropharyngeal sites (4.6 and 19.7 per 100 person-years for chlamydia and gonorrhea, respectively).
Other notable findings included a higher prevalence of gonorrhea in study populations enrolling only men who have sex with men; furthermore, the incidence of chlamydia, gonorrhea, and early syphilis were higher in high-income countries vs low-income countries.
Limitations to the study were that the high prevalence of STIs among individuals initiating therapy may reflect inclusion criteria for some PrEP programs, and the incidence of STIs may have been overestimated due to more frequent testing from more anatomic sites. Furthermore, not all studies reported STI data, and the investigators included only laboratory-confirmed STIs.
These findings underscore the high burden of STIs among individuals initiating PrEP as well as among persistent users of preexposure prophylaxis. The investigators suggested there is an opportunity to integrate global HIV and STI services to control STIs by leveraging the growing infrastructure of preexposure prophylaxis access for individuals with HIV, especially among at-risk or underserved populations.
Ong JJ, Baggaley RC, Wi TE, et al. Global epidemiologic characteristics of sexually transmitted infections among individuals using preexposure prophylaxis for the prevention of HIV infection. JAMA Netw Open. 2019 Dec;2(12):e1917134.