External validation of a prediction tool to estimate the risk of human immunodeficiency virus infection amongst men who have sex with men

A human immunodeficiency virus (HIV) risk assessment tool was previously developed for predicting HIV infection among men who have sex with men (MSM), but was not externally validated. We evaluated the tool's validity for predicting HIV infection in an independent cohort. The tool was assessed using data from a retrospective cohort study of HIV-negative adult MSM who were recruited in Beijing, China between January 2009 and December 2016. High-risk behaviors occurring within 6 months before the survey were evaluated. Area under curve (AUC) of the receiver operating character curve (ROC) was used to quantify discrimination performance; calibration curve and Hosmer–Lemeshow statistic were used for calibration performance valuation; and decision curve analysis (DCA) was used to evaluate clinical usage. One thousand four hundred forty two participants from the cohort were included in the analysis; 246 (17.1%) sero-converted during follow-up. External validation of the tool showed good calibration, the Hosmer–Lemeshow test showed no statistical difference between observed probability and tool-based predictive probability of HIV infection (X(2) = 4.55, P = .80). The tool had modest discrimination ability (AUC = 0.63, 95% confidence interval [CI]: 0.61–0.66). The decision curve analysis indicated that implementing treatment measures based on the tool's predicative risk thresholds ranging from 10% to 30% might increase the net benefit of treatment when compared with treating all or no MSM. The HIV risk assessment tool can predict the actual risk of HIV infection well amongst MSM in China, but it has a moderate ability to discriminate those at high risk of HIV infection.