Short-Term Effects of Cholecalciferol Supplementation on cFGF23 Levels in Children with Chronic Kidney Disease and Vitamin D Insufficiency.

Data on the effect of vitamin D supplementation on fibroblast growth factor 23 (FGF23), in chronic kidney disease (CKD) are scarce. In a prospective interventional study, the effect of vitamin D supplementation on cFGF23 (C-terminal FGF23) levels in children with CKD stages 2-4 was examined. Forty-one children with CKD and vitamin D insufficiency were administered 600,000 units of cholecalciferol over 3 d; 88% of patients achieved sufficiency at 8 wk. Significant increase in serum cFGF23 and phosphate levels was observed in CKD stage 2 after supplementation, but not in CKD stages 3 and 4. There was no correlation of the change in cFGF23 level with baseline or change in bone health parameters (calcium, phosphate, parathormone or alkaline phosphatase) or with change in flow-mediated dilatation (FMD) of the brachial artery. It is concluded that cholecalciferol supplementation increases serum calcium and reduces PTH, but does not adversely affect FGF23 levels in CKD.