The investigators hypothesize that Ketosteril can improve sarcopenia in patients with renal disease without increasing the burden on the kidneys and causing deterioration of renal function. Therefore, this study intends to take patients with CKD stage 3-4 and sarcopenia as the research object, give Ketosteril intervention or not to patients on the base of low-protein diet, and clarify the clinical benefits of Ketosteril prescription for improving sarcopenia in patients with CKD.

Inclusion Criteria:

1. Meet the diagnostic criteria for CKD stage 3-4 (15 ≤eGFR<60 ml/(min*1.73m2)) in the 2012 Kidney Disease Improving Global Outcomes (KDIGO) guideline.
2. Sarcopenia should be diagnosed According to the 2019 Asian Working Group for Sarcopenia (AWGS) diagnostic criteria for sarcopenia: ① Muscle strength: grip strength (< 28 kg for males, < 18 kg for females); ② Physical function: is assessed by walking speed over 6 m (< 1.0 m/s) or five-repetition sit-to-stand test (5STS) (≥ 12 s) or recommended short physical performance battery (SPPB) (≤ 9); ③ Artificial skeletal muscle (ASM) of extremities: Bioelectrical impedance analyzer (BIA) (< 7.0 kg/m2 for males and < 5.7 kg/m2 for females). On the basis of meeting criteria ③, sarcopenia can be diagnosed if at least one of the first two items is met.
3. Patient can walk normally.
4. Provide the written informed consent.

Exclusion Criteria:

1. Patients with diabetes.
2. Obese/overweight patients (body mass index>25 kg/m2)
3. Had previously received renal replacement therapy (including kidney transplantation, hemodialysis, peritoneal dialysis).
4. Patients with new cardiovascular events, uncontrolled acute or chronic cardiac failure within 3 months.
5. Patients with acute infection (C-reactive protein>10 mg/L) or acute exacerbation of chronic diseases that is not under control within 3 months.
6. Patients with cerebrovascular events, severe liver disease, malignant tumor and multiple organ failure.
7. Patients with osteoarthritis, metabolic bone disease, osteonecrosis of the femoral head, hemiplegia and cognitive dysfunction.
8. Patients with hypercalcemia and amino acid metabolism disorder.
9. Those who are allergic to the active ingredients or other excipients of the Ketosteril.
10. Patients with poor compliance, unable to follow the study requirements for diet control.
11. Participated in other interventional clinical trials within 30 days before this study.

Data will be made available upon request pending