Abstract
Key populations (KP), such as female sex workers (FSW) and men who have sex with men (MSM) can engage in multiple behaviors associated with HIV risk, but they are typically categorized by a single defining behavior, i.e., selling sex and sex with a man, respectively. We estimated the prevalence of engaging in multiple KP defining behaviors such as buying/selling sex, receptive anal sex, and injection drug use (IDU) among KP in Uganda. Data were collected at survey offices in four sites (Kampala, Jinja, Mbarara, and Masaka) through respondent-driven sampling. Data across multiple sites were combined and reweighted based on the combined sample size for each population. We fitted weighted multinomial logistic models for additional KP defining behaviors using demographics as predictors, and the simplest plausible model was identified for each KP using the Bayesian Information Criterion. Among FSW and sexually exploited minors under 18 years of age, 21.8% (CI: 20.1-23.5%) ever engaged in anal sex and 12.0% (CI: 10.6-13.3%) ever engaged in IDU in our model. Among MSM, 54.8% (CI: 52.0-57.7%) ever engaged in buying/selling sex and 11.0% (CI: 9.3-12.8%) ever engaged in IDU in the model. While KP are generally viewed as independent groups, our findings demonstrate that KP defining behaviors such as buying/selling sex, anal sex with a man, and IDU are shared across populations, with buying/selling sex particularly common among MSM. Consideration of comprehensive behaviors by outreach and service providers may better inform HIV risk reduction and prevention services for key populations.