Tenofovir, one of the most effective and commonly prescribed antiretroviral medications for HIV/AIDS, is associated with a significant risk of kidney damage and chronic kidney disease that increases over time, according to a study of more than 10,000 patients led by researchers at the San Francisco VA Medical Center and the University of California, San Francisco (UCSF).
The researchers call for increased screening for kidney damage in patients taking the drug, especially those with other risk factors for kidney disease.
In their analysis of comprehensive VA electronic health records, the study authors found that for each year of exposure to tenofovir, risk of protein in urine – a marker of kidney damage – rose 34 percent, risk of rapid decline in kidney function rose 11 percent and risk of developing chronic kidney disease (CKD) rose 33 percent. The risks remained after the researchers controlled for other kidney disease risk factors such as age, race, diabetes, hypertension, smoking and HIV-related factors.
For individual patients, the differences in risk between users and non-users of tenofovir for each year of use were 13 percent vs. 8 percent for protein in urine, 9 percent vs. 5 percent for rapidly declining kidney function and 2 percent vs. 1 percent for CKD. “However, these numbers are based on the average risks in our study population, and patients with more risk factors for kidney disease would be put at proportionately higher risk,” said principal investigator Michael G. Shlipak, MD, MPH, chief of general internal medicine at SFVAMC and professor of medicine and epidemiology and biostatistics at UCSF.
Patients were tracked for an average of 1.2 years after they stopped taking tenofovir. They remained at elevated risk for at least six months to one year compared with those who never took the drug, suggesting that the damage is not quickly reversible, said Shlipak. “We do not know the long-term prognosis for these patients who stop tenofovir after developing kidney disease,” he cautioned.