The Effect of Antioxidant Vitamins on Patients With Diabetes and Albuminuria: A Meta-Analysis of Randomized Controlled Trials

Objective This study aimed to investigate the effect of antioxidant vitamins, including vitamins E and C, on patients with diabetes and albuminuria by conducting a meta-analysis of randomized controlled trials. Design The PubMed, Embase, CENTRAL (the Cochrane Central Register of Controlled Trials at the Cochrane Library), Web of Science, OVID, and www.clinicaltrials.gov (latest search: December 10, 2018) databases were searched. This study was limited to randomized controlled trials. Patients with diabetes and albuminuria were included regardless of diabetic type, and patients must have received treatment with vitamins C or E. Results Ten studies, representing 445 participants, were identified for analysis. Antioxidant vitamins had significant effects on serum creatinine levels (mean difference = −0.11 mg/dL, 95% confidence interval −0.19 to −0.03, P = .007) and systolic pressure (mean difference = −6.02 mm Hg, 95% confidence interval −9.65 to −2.40, P = .001) with low heterogeneity. Antioxidant vitamins had no effect on albuminuria or proteinuria, diastolic blood pressure, glucose, or lipid metabolism. Conclusion This meta-analysis indicated that antioxidant vitamins can benefit kidney function and systolic blood pressure in patients with diabetes and albuminuria. Further studies with larger sample sizes and longer follow-up are needed to completely understand the effect of antioxidant vitamins in these patients. This study aimed to investigate the effect of antioxidant vitamins, including vitamins E and C, on patients with diabetes and albuminuria by conducting a meta-analysis of randomized controlled trials. The PubMed, Embase, CENTRAL (the Cochrane Central Register of Controlled Trials at the Cochrane Library), Web of Science, OVID, and www.clinicaltrials.gov (latest search: December 10, 2018) databases were searched. This study was limited to randomized controlled trials. Patients with diabetes and albuminuria were included regardless of diabetic type, and patients must have received treatment with vitamins C or E. Ten studies, representing 445 participants, were identified for analysis. Antioxidant vitamins had significant effects on serum creatinine levels (mean difference = −0.11 mg/dL, 95% confidence interval −0.19 to −0.03, P = .007) and systolic pressure (mean difference = −6.02 mm Hg, 95% confidence interval −9.65 to −2.40, P = .001) with low heterogeneity. Antioxidant vitamins had no effect on albuminuria or proteinuria, diastolic blood pressure, glucose, or lipid metabolism. This meta-analysis indicated that antioxidant vitamins can benefit kidney function and systolic blood pressure in patients with diabetes and albuminuria. Further studies with larger sample sizes and longer follow-up are needed to completely understand the effect of antioxidant vitamins in these patients.