Limited Utility of HIV RNA Testing to Monitor Oral Preexposure Prophylaxis Use: A Real-World Cohort Study-United States, 2019-2023.

Abstract

The 2021 update of the Centers for Disease Control and Prevention clinical guidelines for human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP) recommended both antigen-antibody (Ag/Ab) and RNA testing at PrEP initiation and routine follow-up. We assessed the real-world use and performance of HIV tests among oral PrEP users. An oral PrEP user cohort was constructed using the HealthVerity database that included linked diagnoses, laboratory tests, and prescriptions from December 2018 to August 2023. Data were stratified by pre-guideline update (2019-2021) and post-guideline update (2022-2023) periods. For each period, we assessed the agreement between same-day HIV Ag/Ab and RNA results and calculated the false-positive rates and positive predictive values of HIV Ag/Ab and RNA tests compared with the adjudicated HIV status. The HIV RNA testing rate for follow-up, per 100 person-years, increased from 16 before to 123 after the guideline update. The positivity rate of HIV RNA tests decreased from 1.39% to 0.22%. Overall agreement between Ag/Ab and RNA results remained high. The false-positive rates of HIV Ag/Ab and RNA testing remained similar, but the positive predictive value of HIV RNA testing for PrEP follow-up decreased from 100% to 67%. We estimated that 8226-9900 RNA tests would be needed for 1 HIV diagnosis earlier than would be detected with Ag/Ab testing alone. HIV RNA testing did not provide additional value to Ag/Ab testing during routine follow-up of oral PrEP users. Considering the cost and logistical complexity of HIV RNA testing, its use as a routine test during follow-up of oral PrEP users warrants reconsideration.