The Effect of Dietary Protein Restriction on the Progression of Diabetic and Nondiabetic Renal Diseases: A Meta-Analysis

Abstract

Background Dietary protein has long been thought to play a role in the progression of chronic renal disease, but clinical trials to date have not consistently shown that dietary protein restriction is beneficial. Purpose To use meta-analysis to assess the efficacy of dietary protein restriction in previously published studies of diabetic and nondiabetic renal diseases, including the recently completed Modification of Diet in Renal Disease Study. Data sources The English-language medical literature published from January 1966 through December 1994 was searched for studies examining the effect of low-protein diets in humans with chronic renal disease. A total of 1413 patients in five studies on nondiabetic renal disease (mean length of follow-up, 18 to 36 months) and 108 patients in five studies of type I diabetes mellitus (mean length of follow-up, 9 to 35 months) were included. Study selection Randomized, controlled studies were selected for nondiabetic renal disease; randomized, controlled studies or time-controlled studies with nonrandomized crossover design were selected for diabetic nephropathy. Data extraction Data in tables, figures, or text were independently extracted by two of the authors. Data synthesis The relative risk for progression of renal disease in patients receiving a low-protein diet compared with patients receiving a usual-protein diet was calculated by using a random-effects model. In five studies of nondiabetic renal disease, a low-protein diet signific…