Association of a Low-Protein Diet With Slower Progression of CKD

Introduction Reducing protein intake is recommended for slowing chronic kidney disease (CKD) progression, but assessment of its true effectiveness is sparse. Methods Using the Maroni formula, we assessed dietary protein intake (DPI) from 24-hour urinary urea excretion in 1594 patients (67% men and 33% women) with CKD, 784 of whom also had 7-day food records. Cause-specific hazard ratios (HRs) and 95% confidence intervals for the competing risks of DPI-associated end-stage renal disease (ESRD) or death were estimated in 1412 patients with baseline glomerular filtration rate ≥15 ml/min per 1.73 m 2 , measured by 51 Cr-EDTA renal clearance (mGFR). Results Overall, mean DPI estimated from urea excretion was 1.09 ± 0.30 g/kg of body weight per day (range = 0.34−2.76); 20% of patients had values > 1.3 g/kg per day, and 1.9% had values  2 . There was no association with mortality. The mean age of the patients was 59 ± 15 years, and mean body mass index was 26.6 ± 5.2 kg/m 2 . Conclusion In this prospective observational study, the lower the baseline DPI, the slower the progression toward ESRD. Most importantly, the absence of threshold for the relation between DPI and ESRD risk indicates that there is no optimal DPI in the range observed in this cohort.