Effect of Protein-Restricted Diet on Nitrogen Balance and Residual Renal Function in Peritoneal Dialysis (PD) Patients


Current therapy recommendations suggest a low protein diet to preserve residual renal function (RRF) before the start of dialysis, but a higher protein intake during dialysis to prevent protein-energy wasting (PEW). We conducted a randomized trial to test whether low protein intake also during treatment with peritoneal dialysis (PD) would be safe and associated with a preserved RRF.

Full Title of Study: “Effect of Protein-Restricted Diet on Nitrogen Balance and Residual Renal Function in PD Patients”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: None (Open Label)
  • Study Primary Completion Date: January 2008

Detailed Description

Dietary protein is the major source of nitrogen excreted as urea by the kidney, and a decreased protein intake has been associated with a retardation of kidney function loss in non-dialysis chronic kidney disease (CKD) patients. While a low protein diet is recommended to end-stage renal disease (ESRD) patients before the start of dialysis to preserve residual renal function(RRF), current therapy recommendations in dialysis are for a normal protein intake of no less than 1.2 g of protein/kg ideal body weight (IBW)/day to prevent protein-energy wasting (PEW). We hypothesized that a lower protein intake would be safe and able to slow the loss of RRF also in dialysis patients and conducted two prospective, randomized trials involving a total of 94 peritoneal dialysis (PD) patients to test our hypothesis.


  • Dietary Supplement: diets contained different levels of protein
    • diets contain protein in the range of 0.6-0.8 or 1.0-1.2 g/kg/d

Arms, Groups and Cohorts

  • Active Comparator: 1
    • low protein diet
  • Active Comparator: 2
    • low protein diet with keto acids
  • Active Comparator: 3
    • high protein diet

Clinical Trial Outcome Measures

Primary Measures

  • nitrogen balance,residual renal function and nutritional status
    • Time Frame: 10 day and 1 year

Participating in This Clinical Trial

Inclusion Criteria

  • age 18-80 years – stable peritoneal dialysis since at least 1 month – with renal function Exclusion Criteria:

  • a high probability (assessed by the recruiting physician) of receiving a kidney transplant within one year – overt infection within the last month – poor compliance in previous dietary prescriptions or irregular check-ups – persistent anorexia, vomiting or diarrhea within the last month – a CRP of more than 30 mg/dL – presence of wasting diseases such as cancer or tuberculosis

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 80 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Shanghai Jiao Tong University School of Medicine
  • Provider of Information About this Clinical Study
    • Qiang Yao, Renji Hospital, Shanghai Jiaotong University, School of Medicine
  • Overall Official(s)
    • Yao Qiang, MD, Ph.D, Principal Investigator, RenJi Hospital

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