Older than 50 and interested in HIV pre-exposure prophylaxis (PrEP)? Talk to your doctor about your kidneys first. That’s the suggestion of a recent retrospective analysis published in the journal AIDS.
There are currently two approved options for PrEP: Truvada (tenofovir disoproxil fumarate/emtricitabine) and Descovy (tenofovir alafenamide/emtricitabine). The older form of tenofovir in Truvada is harder on the kidneys and bones than the newer form in Descovy.
The latest analysis adds to the growing conversation about which HIV prevention pill is right for which people. Impaired kidney function is one reason a clinician might switch someone from Truvada to Descovy. But another recent study published in Open Forum Infectious Diseases found that one in six switches from Truvada to Descovy were not necessary according to lab tests.
In this analysis, Douglas Drak of the University of Sydney, and colleagues analyzed the lab work of 6,808 people who were part of the large Expanded PrEP Implementation in Communities–New South Wales (EPIC-NSW) cohort. Almost all were men, and the median age was 35.
That study showed that Truvada PrEP effectively prevented HIV acquisition. But the researchers also gathered kidney function data at the beginning of the study and at least once more during follow-up. They measured estimated glomerular filtration rate (eGFR), an indicator of how well the kidneys filter a waste product called creatinine out of the blood.
A healthy eGFR is 90 milliliters/minute or more. At the start of the study, 27% of participants already had an eGFR below 90 ml/min, or early-stage kidney disease. These men still had healthy kidneys, but if anyone were to develop kidney problems, it would be them.
Forty-six participants (0.7%) developed kidney problems during the study—a rate five times higher than those seen in earlier PrEP studies, like iPrEX and Partners PrEP. By the end of two years, kidney impairment had increased by 1.34%. But when the researchers broke down the data by age, 14% of men age 50 or above accounted for most of those cases. Indeed, men who were 50 or older when they started Truvada were four times as likely as their younger peers to develop kidney problems at two years. In multivariate modeling, men were a full 15 times more likely to develop chronic kidney disease after age 50.
Men who started the study with an eGFR below 90 ml/min were 29 times more likely to develop further kidney injury over the two years. Interestingly, previous PrEP use, presence of hepatitis C and methamphetamine use were not associated with kidney dysfunction. And neither was taking Truvada every day.
“The incidence of renal impairment was low but substantially higher than reported in previous clinical trials,” wrote Drak and colleagues. “For those with risk factors, more frequent clinical monitoring may be warranted.”
Click here to read the study abstract.
Click here to learn about the difference between TDF and TAF.
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