Brief Report: Frequency of Monitoring Kidney Function in HIV-Uninfected Persons Using Daily Oral Tenofovir Disoproxil Fumarate Pre-exposure Prophylaxis

Abstract

Background: Wide-scale implementation of oral tenofovir-based pre-exposure prophylaxis (PrEP) for HIV prevention is now policy in many settings. However, the optimal frequency for monitoring kidney function remains uncertain. We investigated the impact of 6-monthly compared with 3-monthly creatinine clearance (CrCl) monitoring on the identification of moderate kidney dysfunction, defined as CrCl <60 mL/min.

Methods: Data were from 2 prospective daily oral PrEP studies in Kenya and Uganda: the Partners PrEP Study, a randomized safety, and efficacy trial of PrEP that conducted 3-monthly CrCl monitoring (n = 4404) and the Partners Demonstration Project (n = 954), an open-label delivery study of PrEP that used 6-monthly monitoring. CrCl ≥60 mL/min was required for enrollment in both studies. Abnormal results were followed with confirmatory testing within approximately 1 week. Follow-up was for up to 24 months.

Results: Of 5358 participants included in the analysis, 87% were younger than 45 years, a third were female, and 21% had a baseline CrCl between 60 and 90 mL/min. Confirmed CrCl <60 mL/min events were rare, occurring in 52 individuals (<1%) in 24 months. The 12-month cumulative proportion of persons with CrCl <60 mL/min was 0.2% with 3-monthly screening and 0.5% with 6-monthly screening. Older age (>45 years), lower weight (<55 kg), elevated blood pressure (>140 mm Hg), and baseline CrCl between 60 and 90 mL/min were independently associated with CrCl decline <60 mL/min during follow-up.

Conclusions: In these 2 PrEP studies, with generally young participants, the occurrence and pattern of clinically relevant decline in CrCl were not qualitatively different based on 3- or 6-monthly CrCl monitoring schedule. These data suggest that for most persons receiving PrEP for up to 24 months, less frequent CrCl monitoring would be safe and reduce required expenditures for repeat confirmatory testing.