Efficacy of Vitamin D3 in Patients With Diabetic Nephropathy: An Updated Meta-Analysis

Context Diabetic nephropathy is a common complication of diabetes mellitus with a higher incidence. Renin-angiotensin system blockers, as the main treatment for patients with diabetic kidney disease, can not only reduce albuminuria, but also lead to hyperkalaemia and creatinine. Therefore, additional protective therapeutic interventions are needed. Evidence Acquisition An electronic literature search was conducted in international and domestic databases including PubMed, Embase, CNKI, Scopus, Index Copernicus, DOAJ, and Wanfang database for trials up to January 2017. The search terms used were as follow: "Diabetic Nephropathies", "vitamin D₃", "Cholecalciferol", "Calcitriol", "Alfacalcidol", "Paricalcitol", and "Randomized Controlled Trial". Quality assessments were evaluated with the Newcastle-Ottawa Quality Assessment Scale. Data were extracted by 2 independent reviewers (TJL and WGL). For all analysis, the standard mean difference (SMD) or odds ratio (OR) with 95% confidence intervals (CIs) were calculated, and heterogeneity of the studies was analyzed using I² statistics. Results Twenty-four studies were (1,978 patients) identified in the literature retrieve process. The assessment scores indicated that all the admitted studies were reliable with scores ranging from 6 to 9. The pooled results indicated that vitamin D₃ had a significant effect in reducing albuminuria (MD = -0.23, 95% CI: -0.30, -0.15) and that the vitamin D₃ group had a low ratio of urinary microalbumin to creatinine than the control group (SMD = -0.49, 95% CI: -0.90, -0.08). The results also revealed that vitamin D₃ group had a lower hs-CRP than the control group (MD = -0.80, 95% CI: -1.26, -0.34). Conclusions Based on the evidence of this study, vitamin D₃ could be suggested as a recommended drug for patients with diabetic nephropathy in clinical practice.