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Evidence summaries

Protein Restriction in Diabetic Renal Disease

Low protein intake appears not to slow the progression towards nephropathy in diabetes patients. Level of evidence: "B"

A systemic review 1 included 11 RCTs assessing the efficacy of low-protein diet on renal function in patients with type 1 or 2 diabetic nephropathy. Low protein diet was not associated with a significant improvement in GFR (standardized mean difference [SMD] 1.59 ml/ min, 95% CI -0.57 to 3.75, I² = 76%; p = 0.15). This effect was consistent across the subgroups regardless of type of diabetes, course of diabetes and intervention period. There was no significant difference on improvement of proteinuria and those in normal-protein diet groups (- 0.48, 95% CI-1.70, 0.74, I² = 94%, p = 0.44).

Another meta-analysis 2 included 20 trials with a total of 690 patients in the low-protein diet group and 682 patients in the control group. Low protein diet decreased the urinary albumin excretion rate (SMD 0.62, 95% CI 0.06 to 1.19) and proteinuria (SMD 0.69, 95% CI 0.22 to 1.16) versus the control group. No statistical difference, however, was found in serum creatinine (SMD 0.20, 95% CI -0.26 to 0.66) or in GFR (SMD 0.21, 95% CI -0.29 to 0.71) between the two groups.

Comment: The quality of evidence is downgraded by imprecise results (limited study size for each comparison).

    References

    • Zhu HG, Jiang ZS, Gong PY et al. Efficacy of low-protein diet for diabetic nephropathy: a systematic review of randomized controlled trials. Lipids Health Dis 2018;17(1):141. [PubMed]
    • Li XF, Xu J, Liu LJ et al. Efficacy of low-protein diet in diabetic nephropathy: a meta-analysis of randomized controlled trials. Lipids Health Dis 2019;18(1):82. [PubMed]

Primary/Secondary Keywords