A strict low-protein diet for chronic kidney failure patients can delay dialysis treatment for about a year, according to results of a Johns Hopkins study.
The findings are in sharp contrast to current practice, which is to start dialysis earlier and earlier in patients with end-stage renal disease.
"Our study clearly shows that many of these end-stage patients can be safely managed with diet for substantial intervals after they have reached or passed the usual point for beginning dialysis," says Mackenzie Walser, M.D., lead author and professor of pharmacology, molecular sciences and medicine. "In our diet study, predialysis mortality was only 2.5 percent per year -- much lower than the 24 percent annual mortality from dialysis reported nationwide. Furthermore, nutrition and blood chemical values were well maintained."
In the Hopkins study, published in a January issue of the Journal of the American Society of Nephrology, 76 patients with severe chronic renal failure were put on a very low-protein diet with essential amino acid and/or ketoacid supplements. The supplements provided building blocks of proteins that the patients' bodies could not produce.
Patients were able to postpone dialysis for a median of 353 days, with times varying from less than one week to four years. Diabetic patients fared as well as nondiabetic patients.
The dietary treatment, though often difficult to follow, has no side effects, Walser says. The diet consists mostly of fruits and vegetables; it excludes such high-protein foods as meat, fish, poultry, cheese and milk.
"It seems surprising at first that restricting protein intake in patients does not lead to malnutrition," he says. "But the diet and supplements provide an adequate intake of energy and other essential nutrients, and patients without complicating illnesses adapt well. By contrast, predialysis patients who eat too much protein can develop loss of appetite, nausea and vomiting, which reduce the intake of all nutrients and lead to a decline in nutritional status."
Deferring dialysis remains controversial, says Walser, who authored an editorial on the subject in the March issue of Kidney International along with physicians from Emory University School of Medicine in Atlanta and the University of California-Los Angeles Schools of Medicine and Public Health. They dispute the concerns of many researchers that low-protein diets are impractical in terms of cost and compliance.
The cost of amino acid tablets averages less than the high-protein foods they replace, the authors say. And although some patients take in 25 to 50 percent more protein than recommended, that amount is substantially less than what they were eating before.
Further study is necessary to determine the proportion of patients who could adhere to the diet, Walser says.
Karen Infeld 410-955-1534
E-mail: kinfeld@jhmi.edu
Journal
Journal of the American Society of Nephrology