Protein restriction for diabetic renal disease (Cochrane Review)

A substantive amendment to this systematic review was last made on 26 August 1997. Cochrane reviews are regularly checked and updated if necessary.

Background: Diabetic renal disease (nephropathy) is a leading cause of end-stage renal failure.

Objectives: To determine whether protein restriction slows or prevents progression of diabetic nephropathy towards renal failure.

Search strategy: Computerised databases Medline (1976-1996) and Embase (1974-1996) were searched using the search terms diabetes mellitus, diabetic nephropathy, dietary proteins, diet, protein restricted and uremia. Recent issues of selected journals (Diabetic Medicine, Diabetologia, Diabetes Care, Kidney International, Nephrology Dialysis and Transplantation) were handsearched for papers not yet in the computerised databases. Reference lists of papers were also checked.

Selection criteria: This review was not limited to randomised controlled trials. All trials involving people with insulin-dependent diabetes following a lower protein diet for at least four months were considered since the straight line nature of progression as reflected by glomerular filtration rate means that patients can act as their own controls in a before and after comparison.

Data collection and analysis: Data were extracted for length of follow up, level of protein restriction, renal function and dietary compliance. No studies of the impact of protein restriction on outcomes such as the need for dialysis or transplantation were found. The trials reported only the effect on short-term indicators such as creatinine clearance.

Main results: Overall a protein restricted diet (0.3-0.8 g/kg) does appear to slow the progression of diabetic nephropathy towards renal failure.

Reviewers' conclusions: The results show that reducing protein intake appears to slow progression to renal failure, but some questions remain unanswered. The first is what level of protein restriction should be used? The trials aimed for a daily intake of between 0.3 to 0.8 g/kg of protein. The second concerns compliance in routine care - what level would be acceptable to patients? The third concerns long term outcomes - the present trials use proxy indicators such as creatinine clearance rather than outcomes such as time to dialysis or prevention of end stage renal failure. All trials were carried out in patients with insulin-dependent diabetes. It remains to be seen if a lower protein intake would slow the progression of nephropathy affecting the non-insulin dependent diabetic population.

Citation: Waugh NR, Robertson AM. Protein restriction for diabetic renal disease (Cochrane Review). In: The Cochrane Library, Issue 3, 2003. Oxford: Update Software.

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This is an abstract of a regularly updated, systematic review prepared and maintained by the Cochrane Collaboration. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).

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