Department of Psychology, Ryerson University, Toronto, Ontario, Canada
Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
Sex Transm Infect. 2023 May;99(3):167-172. doi: 10.1136/sextrans-2021-055381. Epub 2022 Jun 14.
While pre-exposure prophylaxis (PrEP) prevents HIV acquisition among gay, bisexual and other men who have sex with men (GBM), PrEP-using GBM may be more likely to engage in sexual behaviours associated with bacterial STIs. We examined associations between PrEP use, condomless anal sex (CAS), number of anal sex partners, oral sex and bacterial STI diagnoses among GBM living in Canada's three largest cities.
Among HIV-negative/unknown-status GBM in the baseline of the Engage cohort study, we fit a structural equation model of the associations between any PrEP use, sexual behaviours and bacterial STI diagnosis. We estimated direct and indirect paths between PrEP use and STI via CAS, number of anal sex partners and oral sex.
The sample included 2007 HIV-negative/unknown status GBM in Montreal, Toronto and Vancouver. There was a significant direct association between PrEP use and current STI diagnosis (β=0.181; 95% CI: 0.112 to 0.247; p<0.001), CAS (β=0.275; 95% CI: 0.189 to 0.361; p<0.001) and number of anal sex partners (β=0.193; 95% CI: 0.161 to 0.225; p<0.001). In the mediated model, the direct association between PrEP use and STIs was non-significant. However, the indirect paths from PrEP to CAS to STIs (β=0.064; 95% CI: 0.025 to 0.120; p=0.008), and from PrEP to greater number of anal sex partners to CAS to STIs were significant (β=0.059; 95% CI: 0.024 to 0.108; p=0.007).
Our study adds to the growing awareness that PrEP use among GBM may be associated with bacterial STIs because PrEP users have more anal sex partners and are more likely to engage in CAS. The results underscore the importance of providing effective STI counselling and regular testing to PrEP users, adapting PrEP care and related STI testing to individual needs, and the need for effective prevention strategies for bacterial STIs.
尽管暴露前预防（PrEP）可预防男同性恋者、双性恋者和其他与男性发生性行为者（GBM）感染艾滋病毒，但使用 PrEP 的 GBM 更有可能发生与细菌性性传播感染（STI）相关的性行为。我们研究了在加拿大三个最大城市居住的 GBM 中，PrEP 使用、无保护肛交（CAS）、肛交性伴侣数量、口交与细菌性 STI 诊断之间的关联。
在 Engage 队列研究的基线中，我们对 HIV 阴性/未知状态的 GBM 中任何 PrEP 使用、性行为与细菌性 STI 诊断之间的关联进行了结构方程模型拟合。我们通过 CAS、肛交性伴侣数量和口交来估计 PrEP 使用与 STI 之间的直接和间接途径。
该样本包括来自蒙特利尔、多伦多和温哥华的 2007 名 HIV 阴性/未知状态的 GBM。PrEP 使用与当前 STI 诊断（β=0.181；95%CI：0.112 至 0.247；p<0.001）、CAS（β=0.275；95%CI：0.189 至 0.361；p<0.001）和肛交性伴侣数量（β=0.193；95%CI：0.161 至 0.225；p<0.001）之间存在显著的直接关联。在中介模型中，PrEP 使用与 STI 之间的直接关联不显著。然而，PrEP 至 CAS 至 STI 的间接途径（β=0.064；95%CI：0.025 至 0.120；p=0.008）以及 PrEP 至更多的肛交性伴侣至 CAS 至 STI 的间接途径均有统计学意义（β=0.059；95%CI：0.024 至 0.108；p=0.007）。
我们的研究增加了人们对 GBM 中 PrEP 使用可能与细菌性 STI 相关的认识，因为 PrEP 使用者有更多的肛交性伴侣，并且更有可能发生 CAS。研究结果强调了向 PrEP 使用者提供有效的性传播感染咨询和定期检测、根据个体需求调整 PrEP 护理和相关性传播感染检测、以及制定有效的细菌性 STI 预防策略的重要性。
