Moderate Protein Restriction in Advanced CKD: A Feasible Option in An Elderly, High-Comorbidity Population. A Stepwise Multiple-Choice System Approach.

Background: Protein restriction may retard the need for renal replacement therapy; compliance is considered a barrier, especially in elderly patients.

Methods: A feasibility study was conducted in a newly organized unit for advanced kidney disease; three diet options were offered: normalization of protein intake (0.8 g/kg/day of protein); moderate protein restriction (0.6 g/kg/day of protein) with a "traditional" mixed protein diet or with a "plant-based" diet supplemented with ketoacids. Patients with protein energy wasting (PEW), short life expectancy or who refused were excluded. Compliance was estimated by Maroni-Mitch formula and food diary.

Results: In November 2017⁻July 2018, 131 patients started the program: median age 74 years (min⁻max 24-101), Charlson Index (CCI): 8 (min-max: 2⁻14); eGFR 24 mL/min (4⁻68); 50.4% were diabetic, BMI was ≥ 30 kg/m² in 40.4%. Normalization was the first step in 75 patients (57%, age 78 (24⁻101), CCI 8 (2⁻12), eGFR 24 mL/min (8⁻68)); moderately protein-restricted traditional diets were chosen by 24 (18%, age 74 (44⁻91), CCI 8 (4⁻14), eGFR 22 mL/min (5⁻40)), plant-based diets by 22 (17%, age 70 (34⁻89), CCI 6.5 (2⁻12), eGFR 15 mL/min (5⁻46)) ( < 0.001). Protein restriction was not undertaken in 10 patients with short life expectancy. In patients with ≥ 3 months of follow-up, median reduction of protein intake was from 1.2 to 0.8 g/kg/day ( < 0.001); nutritional parameters remained stable; albumin increased from 3.5 to 3.6 g/dL ( = 0.037); good compliance was found in 74%, regardless of diets. Over 1067 patient-months of follow-up, 9 patients died (CCI 10 (6⁻12)), 7 started dialysis (5 incremental).

Conclusion: Protein restriction is feasible by an individualized, stepwise approach in an overall elderly, high-comorbidity population with a baseline high-protein diet and is compatible with stable nutritional status.