A Randomized, Double-Blind, Placebo-Controlled, Clinical Trial of High-Dose, Short-Term Vitamin D Administration in the Prevention of Acute Kidney Injury after Cardiac Surgery

Background: Acute kidney injury (AKI) after cardiac surgery is a relatively common complication affecting short- and long-term survival. The renoprotective effect of vitamin D (VitD) has been confirmed in several experimental models. This study was conducted to evaluate the effect of high-dose VitD administration in patients with VitD insufficiency on the incidence of postoperative AKI, the urinary level of tubular biomarkers, and serum anti-inflammatory biomarker after coronary artery bypass graft. Design and Method: In this randomized double-blind controlled clinical trial, the patients were randomly allocated to either the VitD group ( n = 50), receiving 150,000 IU VitD tablets daily for 3 consecutive days before surgery or the control group ( n = 61), receiving placebo tablets. Results: There was no difference in the incidence of postoperative AKI between the groups. Both of the urinary levels of interleukin-18 and kidney injury molecule-1 were significantly increased after the operation ( p < 0.001, for both). Also, the serum level of interleukin-10 was increased after 3 days of VitD supplementation ( p = 0.001). In comparison with the control group, it remained on a higher level after the operation ( p < 0.001) and the next day ( p = 0.03). The patients with AKI had more postoperative bleeding and received more blood transfusion. Conclusion: VitD pretreatment was unable to impose any changes in the incidence of AKI and the urinary level of renal biomarkers. However, high-dose administration of VitD may improve the anti-inflammatory state before and after the operation. Further studies are needed to assess the renoprotective effect of VitD on coronary surgery patients.