Effect of vitamin D supplementation on serum hepcidin levels in non-diabetic chronic kidney disease patients

Introduction: Vitamin D deficiency and anemia frequently coexist. Moreover, vitamin D deficiency is found to play a role in chronic kidney disease (CKD)-associated anemia. We investigated the effect of cholecalciferol on serum hepcidin levels in vitamin D-deficient, non-diabetic individuals with CKD in a randomized, double-blind, placebo-controlled trial.Methods: This study was performed on stored samples of our previously published randomized, double-blind, placebo-controlled trial of cholecalciferol supplementation in non-diabetic patients with stage III-IV CKD and vitamin D deficiency. Stable patients of either sex, aged 18-70 years, with non-diabetic stage III-IV CKD (estimated glomerular filtration rate between 15 and 60 ml/min/1.73 m(2)), and having serum 25-hydroxyvitamin D-3 [25(OH) D] levels <= 20 ng/ml were included. Participants received either two directly observed oral doses of cholecalciferol (300,000 IU) or matching placebo at baseline and at eight weeks. Follow-up was done at 16 weeks. Serum hepcidin levels were analyzed at baseline and at 16 weeks.Results: A total of 120 CKD patients were enrolled. Serum 25(OH) D levels were similar in the placebo and cholecalciferol groups at baseline (13.21 +/- 4.78 ng/ml and 13.40 +/- 4.42 ng/ml; P = 0.88). After 16 weeks, the serum 25(OH) D levels were found to be increased in the cholecalciferol group but not in the placebo group (between-group difference in mean change 23.40 ng/ml; 95% CI: 19.76 to 27.06; P < 0.001). Serum hepcidin levels were similar at baseline (median [IQR]: 33.6 [8.6-77.8] ng/ml vs. 24.6 [9.3-70.7] ng/ml, P = 0.903) and did not vary between groups at 16 weeks (median [IQR]: 41.5 [10.9-75.0] ng/ml vs. 34.8 [12.3-63.75] ng/ml, P = 0.703).Conclusion: Our study provides preliminary data based on which a larger adequately powered clinical trial can be conducted to conclusively assess the impact of vitamin D supplementation on hepcidin levels and anemia in patients with CKD and vitamin D deficiency.