The effectiveness of pre-exposure prophylaxis (PrEP) against HIV acquisition depends on treatment adherence; however, within-person associations between levels of PrEP adherence and engagement in condomless sex have not been well studied. In the context of a demonstration project, 372 men who have sex with men received once-daily PrEP and completed six study visits over 48 weeks. Two-part growth mixture modeling was used to examine the longitudinal trajectory of condomless anal intercourse (CAI) and self-reports of PrEP adherence, controlling for relevant covariates. Over time, greater PrEP adherence was contemporaneously associated with both a higher likelihood of engaging in any CAI and with a greater number of CAI acts. Substance use was also associated with a higher likelihood of engaging in CAI. Contemporaneous associations between self-reported PrEP adherence and CAI suggest that adherence behaviors may be motivated by the desire to mitigate risk of HIV infection; however, exact directionality is unknown.

中文翻译：

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自我报告的暴露前预防 (PrEP) 依从性的提高与男男性行为者中无安全套性行为的增加有关。


暴露前预防 (PrEP) 预防 HIV 感染的有效性取决于治疗依从性；然而，PrEP 坚持程度与无套性行为参与程度之间的人内关联尚未得到充分研究。在示范项目中，372 名男男性行为者每天接受一次 PrEP，并在 48 周内完成了六次研究访问。两部分生长混合模型用于检查无套肛交 (CAI) 的纵向轨迹和 PrEP 依从性的自我报告，并控制相关协变量。随着时间的推移，较高的 PrEP 依从性同时与参与任何 CAI 的可能性较高以及 CAI 行为的数量增加相关。药物使用也与参与 CAI 的可能性较高有关。自我报告的 PrEP 依从性与 CAI 之间的同时关联表明，依从行为可能是出于降低 HIV 感染风险的愿望；然而，确切的方向性尚不清楚。