Background
Sexually transmited infections (STIs) are common among people with HIV (PWH), but there is limited data about risk factors and incidence of STIs in large, representative cohort studies.
Methods
We assessed incidence and risk factors of STIs reported by treating physicians within the Swiss HIV Cohort Study (SHCS). STIs and demographic, clinical and behavioral characteristics were prospectively collected at 6-monthly follow-up visits between October 2017 and November 2019. We used multi-level Poisson regression to assess incidence rate ratios of different STIs.
Results
Among 10,140 study participants, a total of 1,634 STIs in 1,029 SHCS participants were reported over 17,766 person-years of follow up (PYFUP). The overall incidence of any reported STI was 91.9 per 1,000 PYFU (95% CI 85.8 –98.5). Among the 1,634 STI episodes, there were 573 (35.1%) incident cases of syphilis, 497 gonorrhea (30.4%) and 418 chlamydia (25.6%). MSM younger than 50 years represented 21% of the study population, but accounted for 61% of reported STIs. Being male (2.03 adjusted incidence rate ratio (aIRR), 95% CI, 1.36-3.02), MSM (3.62 aIRR, 95% CI, 2.88-4.55), age group 18-34 years (1.78 aIRR, 95%CI, 1.51-2.10), ever reported sexual relationship with occasional partners (6.87 aIRR, 95%CI, 5.40-8.73) and reporting injecting drug use (2.48 aIRR, 95% CI, 1.91-3.23) were associated with a higher risk of incident STIs.
Conclusion
STIs were frequent among PWH and varied considerably between age and risk groups. Screening programs and recommendations for STI testing need to be adapted according to risk factors and demographic characteristics.