October 26, 1994
NOTE: There is no standard printed diet that can be mailed to you. Dr. Mackenzie Walser, the study's lead author, recommends working with your physician to tailor a diet specific to your needs. Your physician can reach Dr. Walser with any questions at 410-955-3832.
Researchers at The Johns Hopkins Medical Institutions have found that a very-low-protein diet before kidney dialysis may reduce patient deaths by three- fourths during the first two years of dialysis.
The study followed 44 patients who were treated with the special diet for at least four months and went on to dialysis. Only 2 died during the first two years of dialysis; national statistics predict 11 to 12 deaths in a group of this size.
Ironically, the very restrictive diet may actually bring patients to dialysis in a better nutritional state.
'That could be why they appear to be doing better for the first couple of years of dialysis," says Josef Coresh, M.D., Ph.D., a Hopkins epidemiologist and author of the study.
However, he emphasizes that the study is preliminary.
"This is a small study, so there's a fair amount of imprecision involved," Coresh explains. Subjects in the study could, for example, share a unique characteristic other than the diet that is responsible for their low death rate.
If a similar reduction in deaths occurs in a broader, more representative population, the diet may become an important tool for prolonging the lives of dialysis patients.
For the past ten years, the number of kidney failure patients has increased 7.8 percent a year. Approximately 200,000 people are currently receiving dialysis treatments as a result of end-stage kidney failure. On average, 24 percent die of complications each year.
The study looked at former patients of Mackenzie Walser, M.D., a Hopkins professor of medicine, and pharmacology and molecular sciences.
Walser, a coauthor of the study, treats patients whose kidneys are deteriorating but have not yet failed. Many patients with ailing kidneys are placed on a low-protein diet. Walser's patients go on a diet with even lower protein limits: no meat, fish chicken, eggs, milk or cheese. To make up for lack of essential components normally provided by protein, patients have to take tablets of amino acids or synthetic substitutes.
The comparison of mortality rates was adjusted for age, gender, race, and other diseases. "Even with these adjustments, we still obtained a highly significant difference in mortality," Walser says.
Walser is currently trying to learn why the low-protein diet may help. He notes that low levels of protein in the bloodstream strongly predict dialysis mortality. An earlier study of Walser's patients showed that the very-low-protein diet produces normal, rather than low, levels of bloodstream protein at the start of dialysis. Walser speculates that this may be because the diet eliminates a part of some high-protein foods that makes it difficult for kidney patients to metabolize protein properly.
Coresh will present the results of the new study at the annual meeting of the American Society of Nephrology on October 28 in Orlando, Fl. The study was funded by the National Institutes of Health through the Johns Hopkins Outpatient Center's General Clinical Research Center.
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