The aim of this study is to evaluate the protective effect of compound α-Keto Acid plus low protein diet in RRF in PD Patients.This is a randomized, open-label, prospective study. 100 patients who meet Inclusion/Exclusion criteria will be randomized into α-Keto Acid group or control group at the ratio of 1:1. α-Keto Acid group will use compound α-Keto Acid plus low protein diet, while control group will use normal protein diet.Compound α-Keto Acid dosage is 0.1/kg/d daily. The effect of compound α-Keto Acid plus low protein diet in RRF will be evaluated after 1 year treatment.