Although high-protein diets appear to be the most efficient way to lose weight, concerns may arise about their innocuity on renal function. The objective of this study is to assess the impact of a weight loss program on renal function. A multicentric cohort-based study was performed using the RNPC© French national weight loss program. Patients with at least two creatinine measurements at the beginning of the program and at the end of the weight loss phase between 1 January 2016 and 1 July 2021 were included. Renal function was assessed by Modification of Diet in Renal Disease (MDRD) equation-based estimated glomerular filtration rate (eGFR). From 4394 patients with two creatinine measurements included, 1579 (35.9%) had normal eGFR (MDRD 90-120 mL/min/1.73 m2), 210 (4.8%) had hyperfiltration (MDRD > 120 mL/min/1.73 m2), 2383 (54.2%) had chronic kidney disease (CKD) grade 2 (MDRD 60-90 mL/min/1.73 m2), and 221 (5.0%) had CKD grade 3 (MDRD 30-60 mL/min/1.73 m2). Multivariable analyses showed no eGFR change for patients in initial CKD grade 2, normal eGFR and hyperfiltration, and a significant increase in CKD grade 3. The RNPC© program avoids renal function impairment during the two first phases, regardless of the initial eGFR.
Keywords: chronic kidney disease; high protein; obesity; weight loss.