Low-protein diet for diabetic nephropathy: a meta-analysis of randomized controlled trials

Am J Clin Nutr. 2008 Sep;88(3):660-6. doi: 10.1093/ajcn/88.3.660.

Abstract

Background: A low-protein diet (LPD) has been proposed for many years to delay the progression of diabetic nephropathy. However, the efficacy of an LPD with respect to renal outcome is disputed.

Objective: We aimed to determine the effect of an LPD on renal function in patients with type 1 or 2 diabetic renal diseases by using a meta-analysis of randomized controlled trials.

Design: Medline, EMBASE, and the Cochrane Central Register of Controlled Trials were searched. Eight studies met the inclusion criteria for our meta-analysis: a duration of >6 mo, use of a randomized control group, availability of outcome data for changes in glomerular filtration rate (GFR) or creatinine clearance rate (CCR), and albuminuria or proteinuria in patients with type 1 or 2 diabetic nephropathy. Data were combined by means of a fixed-effects model. Weighted mean differences (WMD) were calculated for the change in GFR or CCR, glycated hemoglobin (HbA(1c)), and serum albumin between the LPD and control groups. A random-effects model was also used to calculate the standardized mean difference for the change in urinary albumin excretion or proteinuria.

Results: Overall, a change in WMD for GFR or CCR was not significantly associated with an LPD, but a decrease in WMD for HbA(1c) was significant in the LPD group (P = 0.005). Although the benefit of LPD therapy on proteinuria was significant (P = 0.003), great heterogeneity was observed. In a subgroup analysis, LPD resulted in lower serum albumin concentrations.

Conclusion: LPD was not associated with a significant improvement of renal function in patients with either types 1 or 2 diabetic nephropathy.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Diabetes Mellitus, Type 1 / complications
  • Diabetes Mellitus, Type 2 / complications
  • Diabetic Nephropathies / diet therapy
  • Diet, Protein-Restricted*
  • Female
  • Glomerular Filtration Rate
  • Glycated Hemoglobin / metabolism*
  • Humans
  • Male
  • Proteinuria / prevention & control
  • Randomized Controlled Trials as Topic

Substances

  • Glycated Hemoglobin A