The impact of HIV preexposure prophylaxis on bacterial sexually transmitted infection occurrence in MSM: a systematic review and meta-analysis

Objective: To evaluate the effect of preexposure prophylaxis (PrEP) initiation on bacterial sexually transmitted infection (STI) occurrence (overall; chlamydia; gonorrhea; syphilis), in MSM. Design: Systematic review and meta-analysis. Methods: Systematic searches were performed in PubMed, Embase, and Scopus without language restrictions until 1 February 2023. We sought studies reporting data for the estimation of incidence rate ratios (IRR), prevalence ratios or cumulative incidence ratios (the latter in equal time periods before and after PrEP initiation) regarding bacterial STI occurrence. Separate analyses were performed overall for any STI, syphilis, chlamydia and gonorrhea (overall; rectal; urethral; pharyngeal for the two latter conditions); ratios greater than unity denoted increase in STI occurrence after PrEP initiation. Results: Twenty-three eligible studies with 11 776 participants (age range: 18–71 years) with a median follow-up of 12 months were included. Overall, PrEP initiation was associated with a significant increase in the occurrence of any STI (pooled effect size: 1.15, 95% confidence interval (CI): 1.04–1.26), any gonorrhea (pooled effect size: 1.17, 95% CI: 1.02–1.34), any chlamydia (pooled effect size: 1.31, 95% CI: 1.09–1.58) and rectal chlamydia (pooled effect size: 1.31, 95% CI: 1.05–1.64), whereas a borderline increase was found in urethral chlamydia (pooled effect size: 1.25, 95% CI: 0.99–1.60, P = 0.064). Changes in pharyngeal chlamydia and site-specific gonorrhea occurrence did not reach statistical significance. Syphilis showed virtually no change after PrEP initiation (pooled effect size: 0.99, 95% CI: 0.72–1.37). Conclusion: These results highlight the need for more comprehensive, accessible STI testing to tackle bacterial STI infections in PrEP users.