Renal Function Following Three Distinct Weight Loss Dietary Strategies During 2 Years of a Randomized Controlled Trial

• Autores: Amir Tirosh, Rachel Golan, Ilana Harman-Boehm, Yaakov Henkin, Dan Schwarzfuchs, Assaf Rudich, Julia Kovsan, Georg M. Fiedler, Matthias Blüher, Michael Stumvoll, Joachim Thiery, Meir J. Stampfer, Iris Shai
• Localización: Diabetes care, ISSN-e 0149-5992, Vol. 36, Nº. 8, 2013 (Ejemplar dedicado a: Diabetes), págs. 2225-2232
• Idioma: inglés
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• Resumen

  • This study addressed the long-term effect of various diets, particularly low-carbohydrate high-protein, on renal function on participants with or without type 2 diabetes. In the 2-year Dietary Intervention Randomized Controlled Trial (DIRECT), 318 participants (age, 51 years; 86% men; BMI, 31 kg/m^sup 2^; mean estimated glomerular filtration rate [eGFR], 70.5 mL/min/1.73 m^sup 2^; mean urine microalbumin-to-creatinine ratio, 12:12) with serum creatinine <176 μmol/L (eGFR ≥30 mL/min/1.73 m^sup 2^) were randomized to low-fat, Mediterranean, or low-carbohydrate diets. The 2-year compliance was 85%, and the proportion of protein intake significantly increased to 22% of energy only in the low-carbohydrate diet (P < 0.05 vs. low-fat and Mediterranean). We examined changes in urinary microalbumin and eGFR, estimated by Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration formulas. Significant (P < 0.05 within groups) improvements in eGFR were achieved in low-carbohydrate (+5.3% [95% CI 2.1-8.5]), Mediterranean (+5.2% [3.0-7.4]), and low-fat diets (+4.0% [0.9-7.1]) with similar magnitude (P > 0.05) across diet groups. The increased eGFR was at least as prominent in participants with (+6.7%) or without (+4.5%) type 2 diabetes or those with lower baseline renal function of eGFR <60 mL/min/1.73 m^sup 2^ (+7.1%) versus eGFR ≥60 mL/min/1.73 m^sup 2^ (+3.7%). In a multivariable model adjusted for age, sex, diet group, type 2 diabetes, use of ACE inhibitors, 2-year weight loss, and change in protein intake (confounders and univariate predictors), only a decrease in fasting insulin (β = -0.211; P = 0.004) and systolic blood pressure (β = -0.25; P < 0.001) were independently associated with increased eGFR. The urine microalbumin-to-creatinine ratio improved similarly across the diets, particularly among participants with baseline sex-adjusted microalbuminuria, with a mean change of -24.8 (P < 0.05). A low-carbohydrate diet is as safe as Mediterranean or low-fat diets in preserving/improving renal function among moderately obese participants with or without type 2 diabetes, with baseline serum creatinine <176 μmol/L. Potential improvement is likely to be mediated by weight loss-induced improvements in insulin sensitivity and blood pressure.