Very low-protein diet of no additional benefit in CKD patients: Study
Italy: A long-term pragmatic trial found adherence to protein restriction to be low in patients with chronic kidney disease (CKD) under stable nephrology care. Also, the study showed that prescribing a very low-protein diet supplemented with keto analogs (sVLPD) versus a standard low-protein diet (LPD) is safe but offers no additional advantage with regards to patients' survival or kidney.
The study was published in The American Journal of Clinical Nutrition on 30 December 2021.
As it is not defined whether sVLPD compared to standard LPD improves outcomes in CKD patients under stable nephrology care, Vincenzo Bellizzi, and the team, therefore, Vincenzo Bellizzi and the team aimed to compare the effectiveness of sVLPD vs LPD in patients regularly seen in tertiary nephrology care.
The study included CKD patients stage 4-5 and were followed for at least six months. They were randomized to receive sVLPD or LPD (0.35 or 0.60 g/kg Ideal Body Weight (IBW)/day, respectively), stratified by center and CKD stage. Time to renal death, defined as the first event between end-stage renal disease (ESRD) and all-cause mortality was the primary outcome. Secondary outcomes were the single components of the primary outcome, cardiovascular outcome, and nutritional status.
A total of 223 patients (sVLPD n = 107; LPD n = 116) were analyzed. Mean age was 64 years, 61% were male, 35% had diabetes.
Based on the study, the researchers found the following:
- Median protein intake (PI), that was 0.8 g/kg IBW/day at baseline in both groups, was 0.83 and 0.60 g/kg IBW/day in LPD and sVLPD, respectively, during the trial with a large decrease only in sVLPD.
- During a median of 74.2 months, 180 renal deaths were recorded (141 dialysis and 39 deaths before dialysis).
- Risk of renal death did not differ in sVLPD vs LPD (HR 1.17).
- No difference was observed for ESRD (HR 1.12), mortality (HR 0.95) or time to fatal/non-fatal cardiovascular events.
- After 36 months, still active patients were 45 in sVLPD and 56 in LPD.
- No change of nutritional status emerged during the study in any arm.
"This long-term pragmatic trial found that in CKD patients under stable nephrology care, adherence to protein restriction is low," wrote the authors. "Prescribing sVLPD versus standard LPD was safe but does not provide additional advantage to the kidney or patient survival."
Reference:
Vincenzo Bellizzi, Simona Signoriello, Roberto Minutolo, Biagio Di Iorio, Paola Nazzaro, Carlo Garofalo, Patrizia Calella, Paolo Chiodini, Luca De Nicola, for the ERIKA Study Investigators of the Italian Society of Nephrology-Conservative Therapy of CKD Work Group, No additional benefit of prescribing a very low-protein diet in patients with advanced Chronic Kidney Disease under regular nephrology care: a pragmatic, randomized, controlled trial, The American Journal of Clinical Nutrition, 2021;, nqab417, https://doi.org/10.1093/ajcn/nqab417
