Pre‐exposure prophylaxis (PrEP) adherence questionnaire: Psychometric validation among sexually transmitted infection patients in China

Abstract

Background: Ensuring adherence guarantees the efficacy of pre‐exposure prophylaxis (PrEP). Methods: We conducted a cross‐sectional study among 816 sexually transmitted infection (STI) patients in Shanghai. The questionnaire included self‐reported demographic characteristics, self‐administered items on adherence to free oral PrEP, and PrEP uptake behavior measurement. We conducted item analysis, reliability analysis, validity analysis and receiver operating character-istic (ROC) curve analysis. Results: Not all items were considered acceptable in the item analysis. The questionnaire had a McDonald’s ω coefficient of 0.847. The scale‐level content validity index (CVI) was 0.938 and the item‐level CVI of each item ranged from 0.750 to 1. In exploratory factor analysis, we introduced a four‐factor model accounting for 79.838% of the aggregate variance, which was validated in confirmatory factor analysis. Adding PrEP adherence questionnaire scores contributed to prediction of PrEP uptake behavior (p < 0.001) in regression analysis. The maximum area under the ROC curve was 0.778 (95% IC: 0.739–0.817). Conclusion: The PrEP adherence questionnaire presented psychometric validation among STI patients.