Effects of Ketoanalogue Supplements on Patients Receiving Continuous Ambulatory Peritoneal Dialysis: A Multicenter, Randomized, Double-Blinded, Placebo-Controlled Study

Background: Evidence of the effects of ketoanalogue supplements on residual kidney function (RKF) in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) is limited. This study aimed to evaluate the efficacy and safety of ketoanalogues in preserving RKF in CAPD patients.

Methods: This 1-year multicenter, randomized, double-blinded, placebo-controlled trial involved 153 CAPD patients across six centers. Patients were randomly assigned to either the keto acid (KA, 100 mg/kg per day) or placebo group (PBO), both with a protein intake of 1.0 g/kg ideal body weight. The primary outcome was the changes in RKF, evaluated based on 24-hour creatinine and urea clearance, and secondary outcomes included dialysis adequacy, peritoneal function, nutritional status, and quality-of-life scores.

Results: The decline in RKF was 1.89 (0.44, 2.98) and 1.56 (0.35, 3.14) mL/min/1.73 m² in the KA and PBO groups, respectively, with no difference observed (p = 0.89). There were no differences in dialysis adequacy, peritoneal function, nutritional status, or quality-of-life scores between the groups. In subgroup analyses, for patients with early peritoneal dialysis (PD) initiation, patients in the KA group had a significantly lower decline in RKF compared with the PBO group (1.34 vs. 4.79 mL/min/1.73 m², p = 0.02); however, there is no significant difference between the groups in patients with late PD initiation (1.89 vs. 1.23 mL/min/1.73 m², p = 0.17).

Conclusions: Ketoanalogues did not reduce the decline in RKF on the basis of a protein-restricted diet in patients receiving CAPD; however, its effect on patients with early PD initiation needs further investigation.