Hypoproteic diets are most often discussed for patients with chronic kidney disease (CKD) who do not receive dialysis.
A very low-protein diet supplemented with ketoanalogues of essential amino acids(keto-diet) proved effective in ameliorating metabolic disturbances of advanced CKD and delaying the initiation of dialysis without deleterious effects on nutritional status.
Several recent studies report that the keto-diet could also slow down the rate of decline in renal function, with better outcomes after the initiation of dialysis. Results of a single-centre randomized controlled trial addressing the rate of CKD progression revealed a 57% slower decline in renal function with the keto-diet compared with a conventional low-protein diet (LPD). The keto-diet allowed the safe management of selected patients with stage 4-5 CKD, delaying dialysis for almost 1 year, with a major impact on patient quality of life and health expenditures. Therefore, the keto-diet could be a link in the integrated care model. Careful selection of patients, nutritional monitoring, and dietary counselling are required.
Low protein diets (LPDs) are milestones in chronic kidney disease (CKD). Concerns over compliance and safety limit their use. The aim of this study was to test the feasibility and main results of a multiple-choice approach to LPDs adapted to patient preferences.
Methods
From December 2007 to January 2013, all CKD patients (stages 4/5; progressive stage 3) without contraindications (malnutrition, short life expectancy), were offered two main LPDs (proteins 0.6 g/kg daily): Vegan supplemented (LPD-KA) or with “aproteic” commercial food (LPD-ACF). LPDs followed a qualitative approach based on forbidden and allowed food; one to three free meals per week, and flexible control policy (1–3 mo). Start of dialysis, death, and combined outcome (death–dialysis) were analyzed by Kaplan-Meier curves and Cox model. Comparison with dialysis in patients with glomerular filtration rate (GRF) <15 mL/min, (corresponding to “early” dialysis start) employed standardized mortality rates, with respect to the Italian and the United States Dialysis Registry.
Results
One hundred eighty-five patients (222 patient-years) started at least a trial of LPD-KA, 122 (177 patients-years) LPD-ACF; only 3 patients with GFR <30 mL/min denied an LPD trial. Patients who chose LPD-KA were younger than those on LPD-ACF (63 versus 74 y), had less comorbidity (82% versus 93%), higher proteinuria (1.4 versus 0.7 g/d) and lower GFR (17 versus 23 mL/min) (P < 0.001). Median daily protein intake was 0.7 g/kg on both diets (Maroni-Mitch formula). The combined outcome (death or dialysis) was not influenced by the diet chosen (Cox analysis). The relative risk for death on the diet (patients with GFR <15 mL/min) was 0.5 with respect to the Italian Registry and 0.3 to the United States Dialysis Registry. The diets had comparable costs (1 y on dialysis: 50 patient-years on LPD).
Conclusions
The choice of diet is strictly linked to patient characteristics, thus supporting a multiple-choice offer. Once corrected for baseline data, both LPDs led to similar results, suggesting at least survival equivalence with dialysis, at a lesser cost.
