Adequate Protein Dietary Restriction in Diabetic and Nondiabetic Patients With Chronic Renal Failure Carlo Meloni, MD,* Paola Tatangelo, MD,* Silvia Cipriani, MD,† Valeria Rossi, MD,† Concetta Suraci, MD,‡ Carmela Tozzo, MD,† Bernardo Rossini, MD,† Annalisa Cecilia, MD,† Damiano Di Franco, MD,† Emilia Straccialano, MD,† and Carlo U. Casciani, MD† Objective: To evaluate whether a dietary protein restriction is useful for slowing the progression of chronic renal failure (CRF) in diabetic and nondiabetic patients and to analyze the possible risk of malnutrition after such a dietary regimen. Design: Prospective, randomized case-control clinical trial. Setting: Nephrology outpatients. Patients and other participants: A total of 169 patients, 89 affected with CRF and chronic hypertension and 80 affected with overt diabetic nephropathy (24 suffering from type 1 and 56 from type 2 diabetes) and chronic hypertension. Intervention: Diabetic patients and nondiabetic patients were randomly divided into 2 groups: 40 diabetic patients received a low-protein diet (0.8 g/kg/day) and 40 were maintained on a free protein diet; similarly, 44 nondiabetic patients received a low-protein diet (0.6 g/kg/day) and 45 were maintained on a free protein diet. The investigation lasted 1 year. Main outcome measure: Renal function and nutritional status. Results: At the end of the study, there were no statistically significant differences in renal function between treated and nontreated diabetic patients, whereas treated nondiabetic patients showed a lower decrease in renal function compared with the nontreated group. In both diabetic and nondiabetic patients, the mean body weight and obesity index decreased significantly in treated patients compared with nontreated ones. Serum albumin and prealbumin were stable in all patients during the whole study time, and there were no other signs of malnutrition. Conclusion: An adequate dietary protein restriction is accepted by patients, and it is well tolerated during a 12-month follow-up. Without any sign of malnutrition, it is possible to get near the ideal body weight and to reduce the obesity index and the body mass index, which are both well-established risk factors for developing cardio- vascular pathology. In nondiabetic patients only, we observed a significant slowing of the progression of renal damage. © 2004 by the National Kidney Foundation, Inc. C HRONIC RENAL FAILURE (CRF) pro- gression depends on many factors, 1 and the importance of trying to slow the progression of this condition is well known, whether for clinical, so- cial, or economic reasons. 2 On therapeutic grounds, to slow the progression of CRF, it is important to obtain good control of glycemic status in diabetic nephropathy, and optimal control of blood pressure, proteinuria, and an appropriate protein intake in all nephropathic patients. 3,4 The effect of the restric- tion of protein intake on the progression of CRF is shown on rats with renal failure, 5,6 whereas the therapeutic efficacy of dietary protein restriction on patients with CRF, especially on patients with dia- betic nephropathy, still remains controversial. 7-9 The exact protein intake necessary to avoid malnu- trition in different kinds of nephropathy is also controversial. 9,10 *Nephrology and Dialysis Unit, S. Eugenio Hospital, Rome, Italy. †Clinical Surgery Dept., Tor Vergata University, Rome, Italy. ‡Metabolic Disorders Dept., S. Eugenio Hospital, Rome, Italy. Address reprint requests to Carlo Meloni, MD, U.O.C. Nefro- logia e Dialisi, Ospedale S. Eugenio, P.le Umanesimo 10, 00144 Roma, Italy. E-mail: jumel@tin.it © 2004 by the National Kidney Foundation, Inc. 1051-2276/04/1404-0004$30.00/0 doi:10.1053/j.jrn.2004.07.011 Journal of Renal Nutrition, Vol 14, No 4 (October), 2004: pp 208-213 208