LAUSR

Vitamin D deficiency is frequent in pediatric nephrology. The 2017 European guidelines recommend keeping 25OH vitamin D (25-D) levels within the 75–120 nmol/L range, ideally with daily supplementation. Intermittent supplementation with D3 has also been proposed. We aimed to assess the influence of our local protocol of intermittent vitamin D supplementation on the evolution of 25-D levels between baseline and 2 months. VITATOL is a prospective single-center study performed in our tertiary unit in children and teenagers followed for chronic kidney disease (CKD), kidney transplantation, or stable chronic nephrotic syndrome with 25-D levels below 75 nmol/L. Intermittent oral cholecalciferol (100,000 IU) was administered depending on baseline vitamin D levels and body weight. The primary outcome was the change in 25-D levels between baseline and 2 months. Secondary outcomes were the evolution of the main mineral biomarkers. Thirty-seven patients were included. Two months after beginning supplementation, corresponding to a median(min-max) of 46 (14–79) days after the last dose of vitamin D, 25-D levels increased from 50 to 76 nmol/L ( p  < 0.001), 18 patients having 25-D levels within the target range and 2 above. All patients displayed 25-D levels above 50 nmol/L. There were no significant changes in phosphate, PTH, alkaline phosphatase, and FGF23 levels before and after supplementation. Calcium levels increased from 2.39 to 2.44 mmol/L ( p  = 0.017), but no differences in calciuria and urinary calcium/creatinine ratio were observed. Conclusion : This vitamin D supplementation protocol using intermittent moderate doses of cholecalciferol seems efficient in 54% of cases, with neither significant overdose nor hypercalciuria. What is Known: • Vitamin D deficiency is frequent in pediatric nephrology. • The 2017 European guidelines recommend keeping 25OH vitamin D levels within the 75–120 nmol/L range ideally with daily supplementation, but intermittent supplementation with D3 has also been proposed. What is New: • We assessed the influence of a local protocol of intermittent vitamin D supplementation on the evolution of 25-D levels between baseline and 2 months in children and teenagers followed in pediatric nephrology. • The intermittent cholecalciferol supplementation protocol seems efficient in 54% of cases, with neither significant overdose nor hypercalciuria.