Efficacy of low-protein diet for diabetic nephropathy: a systematic review of randomized controlled trials.
Study Goal
The researchers aimed to determine whether a low-protein diet (LPD) improves renal function in patients with type 1 or 2 diabetic nephropathy through a meta-analysis of randomized controlled trials.
Results Summary
The study found that LPD did not significantly improve glomerular filtration rate (GFR) or proteinuria in patients with diabetic nephropathy. Subgroup analysis indicated that LPD might even increase proteinuria in type 2 diabetes patients.
Population
Patients with type 1 or 2 diabetic nephropathy.
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
low-protein diet (LPD) | decrease | kidney disease | - | - | is believed to be beneficial in slowing the progression | #1 |
low protein diet | increase | protein, sugar and lipid metabolism | - | - | can improve | #2 |
low protein diet | decrease | symptoms and complications of renal insufficiency | - | - | reduce | #3 |
LPD | no change | GFR | patients with type 1 or 2 DN | 1.59 ml·min-1·1.73 m-2, 95% CI -0.57, 3.75 | was not associated with a significant improvement | #4 |
LPD | no change | proteinuria | patients of LPD and those in normal-protein diet groups | -0.48, 95%CI-1.70, 0.74 | was no significant difference on improvement | #5 |
LPD | increase | proteinuria | patients with type 2 diabetes | 1.32, 95% CI 0.17, 2.47 | resulted in increased excretion | #6 |
LPD | no change | renal function | patients with either type 1 or 2 diabetic nephropathy | - | was not significantly associated with improvement | #7 |
BACKGROUND: A low-protein diet (LPD) is believed to be beneficial in slowing the progression of kidney disease. It is reported that low protein diet can improve protein, sugar and lipid metabolism, and reduce the symptoms and complications of renal insufficiency. However, there has been controversial regarding the effects of protein restriction on diabetic nephropathy (DN). OBJECTIVE: To investigate the efficacy of LPD on renal function in patients with type 1 or 2 DN by meta-analysis of randomized controlled trials (RCTs). DESIGN: PubMed, MEDLINE, EMBASE and China National Knowledge Infrastructure databases were searched. Eleven randomized controlled trials met the inclusion criteria, of which 10 were English and 1 was Chinese. The primary outcome was a change in glomerular filtration rate (GFR). The secondary outcome was a change in proteinuria. Random-effects models were used to calculate the standardized mean difference (SMD) and the corresponding 95% confidence intervals (CI). Subgroup analyses were also performed. RESULTS: Our research indicated that LPD was not associated with a significant improvement in GFR (1.59 ml · min-1 · 1.73 m-2, 95% CI -0.57, 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. Our results also showed that there was no significant difference on improvement of proteinuria in patients of LPD and those in normal-protein diet groups (- 0.48, 95%CI-1.70, 0.74, I2 = 94%, p = 0.44). Subgroup analysis revealed that LPD resulted in increased excretion of proteinuria in patients with type 2 diabetes (1.32, 95% CI 0.17, 2.47, I2 = 86%, p = 0.02). CONCLUSION: The present research showed that LPD was not significantly associated with improvement of renal function in patients with either type 1 or 2 diabetic nephropathy. Although these results do not completely eliminate the possibility that LPD is beneficial for patients with diabetic nephropathy, it does not seem to be significant benefit to renal function.