We have read the study by Chen et al.1 published in the Journal of Renal Nutrition on the effects of ketoanalogue supplements on residual renal function (RKF) in patients undergoing continuous ambulatory peritoneal dialysis. Although the study did not show an overall difference in RKF decline between the restricted-protein diet with ketoanalogue (KA) and the control group, subgroup analysis suggested that KA may have a potential protective effect on RKF in early peritoneal dialysis patients with baseline RKF ≥7.5 mL/min/1.73 m2.