Study: Diuretics a Risk to Kidney Patients

The common practice of using diuretics to treat acute kidney failure may do more harm than good, according to a new California study.

Patients whose kidneys go into sudden failure are often given diuretics -- drugs designed to help rid the body of accumulating fluid. But the study, reported in today’s Journal of the American Medical Assn., found that patients given these drugs had a 68% higher death rate than those who were not.

The authors and several kidney experts stressed that the study cannot conclude for sure that the diuretics caused the increased death rate. For example, on average, the patients given diuretics were older and sicker to begin with, and while the authors tried to control for such factors, they may not have been able to do so perfectly.

But the findings add to a body of research suggesting that diuretics often may do little good for such patients. It suggests that doctors must closely monitor people with acute kidney failure and make sure they don’t delay other treatments, such as dialysis, if the patients are not responding to diuretics.

The study examined only patients with acute kidney failure, and it has no bearing on patients with chronic kidney failure.

The study was conducted by a team of researchers led by Dr. Ravindra L. Mehta, a professor of medicine and director of the clinical nephrology and dialysis programs at UC San Diego. The scientists gathered data from 552 intensive-care patients with acute kidney failure. Of these, well over half of the patients had been treated with diuretics.

The scientists found that as well as increased death rates, the patients who had been given diuretics for acute kidney failure also had a higher rate of developing chronic kidney failure that required dialysis.

The death rate was especially high in patients who failed to quickly respond to the diuretics with an increased flow of urine.

“I think this should call for a reappraisal of our frequent use of diuretics in critically ill patients with acute kidney failure,” Mehta said. “We are all trying to do our best for patients who have kidney failure ... but oftentimes, we may not be helping them at all.” Tackling kidney problems quickly is crucial, Mehta said, because studies show that even a small amount of kidney malfunction can significantly increase the chance of death for people who are seriously ill.

“It’s an interesting study, because it kind of goes against what almost everybody does in taking care of critically ill people when their urine output drops,” said Dr. Elaine Kamil, clinical director of pediatric nephrology at Cedars-Sinai Medical Center and president of the medical advisory board for the National Kidney Foundation of Southern California.

But Dr. Richard Lafayette, an associate professor of medicine and clinical chief in the division of nephrology at Stanford University, said the evidence against the use of diuretics is still not strong enough to warrant a change in medical practice.

Although the research is well done, he said, it can’t pinpoint cause and effect. That would require a clinical trial in which similar patients are randomly assigned to a group that is given diuretics and one that is not.