More than half of patients who develop chronic kidney disease while taking proton pump inhibitors (PPI) don’t experience acute kidney problems beforehand, according to a study published Feb. 22 in Kidney International.

Researchers at Washington University School of Medicine in St. Louis and the Veterans Affairs St. Louis Health Care System analyzed data from the Department of Veterans Affairs databases on 125,596 new users of PPIs and 18,436 new users of other heartburn drugs referred to as H2 blockers. The latter are much less likely to cause kidney problems but often aren’t as effective.

Over five years of follow up, the researchers found that more than 80% of PPI users did not develop acute kidney problems. However, more than half of the cases of chronic kidney damage and end-stage renal disease associated with PPI use occurred in people without acute kidney problems.

In contrast, among new users of H2 blockers, 7.67% developed chronic kidney disease in the absence of acute kidney problems, and 1.27% developed end-stage renal disease.

“Doctors must pay careful attention to kidney function in their patients who use PPIs, even when there are no signs of problems,” cautioned Al-Aly, who also is the VA’s associate chief of staff for research and education and co-director of the VA’s Clinical Epidemiology Center.

“In general, we always advise clinicians to evaluate whether PPI use is medically necessary in the first place because the drugs carry significant risks, including a deterioration of kidney function.”