Effect of Nonsupplemented Low-Protein Diet on the Initiation of Renal Replacement Therapy in Stage 4 and 5 Chronic Kidney Disease: A Retrospective Multicenter Cohort Study in Japan.

OBJECTIVE: In subjects with chronic kidney disease (CKD), the effect of low-protein diet (LPD) is expected to alleviate uremic symptoms. However, whether LPD is effective in preventing loss of kidney function is controversial. The aim of this study was to evaluate the association between LPD and renal outcomes. METHODS: We conducted a multicenter cohort study of 325 patients who suffered CKD stage 4 and 5 with eGFR ≥10 mL/min/1.73 m,2 between January 2008 and December 2014. The primary diseases of the patients were chronic glomerulonephritis (47.7%), nephrosclerosis (16.9%), diabetic nephropathy (26.2%), and others (9.2%). The patients were divided into four groups, based on the mean protein intake (PI)/day, group 1 (n = 76): PI < 0.5 g/kg ideal body weight/day, group 2 (n = 56): 0.5 ≤ PI < 0.6 g/kg/day, group 3 (n = 110): 0.6 ≤ PI < 0.8 g/kg/day, group 4 (n = 83): PI ≥ 0.8 g/kg/day. Dietary supplementation with essential amino acids and ketoanalogues was not used. The outcome measure was occurrence of renal replacement therapy (RRT) (hemodialysis, peritoneal dialysis, renal transplantation (excluding preemptive transplantation)) and all-cause mortality until December 2018. Cox regression models were used to examine whether LPD was associated with the risk of outcomes. RESULTS: During a mean follow-up of 4.1 ± 2.2 years. Thirty-three patients (10.2%) died of all causes, 163 patients (50.2%) needed to start RRT, and 6 patients (1.8%) received a renal transplant. LPD therapy of 0.5 g/kg/day or less was significantly related to a lower risk of RRT and all-cause mortality [Hazard ratio = 0.656; 95% confidence interval, 0.438 to 0.984, P = .042]. CONCLUSIONS: These results suggest that non-supplemented LPD therapy of 0.5 g/kg/day or less may prolong the initiation of RRT in stage 4 and 5 CKD patients.