In a February 2014 online edition of AIDS, new results from the iPrEx study reports that using Truvada as PrEP does not seriously harm kidney health over time. Mild changes in kidney function were reported while on PrEP, specifically lower creatinine clearance, but kidney function returned to normal after PrEP was stopped.
Kidney dysfunction occurs in some HIV-positive people who use tenofovir (Viread), which is one of the drugs found in Truvada. Most of the time the dysfunction is mild and resolves after tenofovir is withdrawn from the regimen. However, a few people — especially those with pre-existing kidney disease or a family history for it — have had more serious kidney problems that persisted when Truvada was stopped. The iPrEx team wanted to see if the same is true for HIV-negative individuals.
iPrEx followed 2,499 HIV-negative men and transgender women who have sex with men. Regular blood and urine tests were done to follow changes in creatinine clearance, serum phosphorus, and excess protein and glucose — all of which may indicate some level of kidney dysfunction.
Compared to those on placebo, results showed a small but significant decrease in creatinine clearance in those who were taking Truvada (-2.4 ml/min vs -1.1). This was first noticeable about four weeks after starting PrEP, and continued until Truvada was stopped. After it was stopped, this level returned to normal (-0.1 ml/min vs 0.0). Further, the change in creatinine clearance did not vary by race, age or history of hypertension. (This result remained significant when the study participants were broken into groups who had detectable drug levels in blood at the same time as kidney function was assessed vs. those on placebo.)
No changes in urine protein or glucose were seen, although serum phosphorus levels decreased slightly in those on Truvada, but not significantly.
The study team supports the CDC’s recommendations for using routine kidney tests to monitor serum creatinine levels in people who are on Truvada for PrEP.
MM Solomon, et al. Changes in Renal Function Associated with Oral Emtricitabine/Tenofovir Disoproxil Fumarate use for HIV Pre-Exposure Prophylaxis. AIDS. February 2014.