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Kidney Week

Abstract: PO2303

Effect of Cholecalciferol Supplementation on FGF-23 in Children with CKD

Session Information

Category: Pediatric Nephrology

  • 1700 Pediatric Nephrology

Authors

  • Chu, Stephen M., Johns Hopkins University, Baltimore, Maryland, United States
  • Atkinson, Meredith A., Johns Hopkins University, Baltimore, Maryland, United States
Background

Cholecalciferol increases total vitamin D levels in children with chronic kidney disease (CKD), but by increasing serum phosphate levels may also increase levels of fibroblast growth factor 23 (FGF23), which is associated with adverse outcomes in both adults and children with CKD. Our objective was to quantify changes in FGF23, α-klotho and vitamin D binding protein (VDBP) in children participating in a vitamin D supplementation trial.

Methods

We utilized stored serum samples from a 4-week pilot randomized controlled trial of supplementation with 4000 (high dose) vs. 400 (DRI) IU per day of cholecalciferol in children with mild-to-moderate CKD. Intact and C-terminal FGF23, soluble α-klotho, and VDBP were measured using commercially-available ELISAs in the Johns Hopkins Institute for Clinical and Translational Research Core Laboratory. Statistical analyses conducted using Stata 14.

Results

Thirty-four children were included in the analysis; 17 received the intervention dose of 4000 IU cholecalciferol, and 17 received the control dose of 400 IU. The mean (SD) age of the cohort was 10.9 (5.8) years, 26.5% female, 23.5% black, 58.8% white, and 17.7% other race. Mean (SD) GFR at baseline was 60 (17.6) ml/min/1.73m2. Median (IQR) baseline total vitamin D level was 29 (20, 34) ng/ml in the control arm and 32 (23, 39) in the intervention arm. Total vitamin D level did not change significantly after 4 weeks of supplementation in the control arm, but was increased to 38.5 (31, 50) in the intervention arm (p=0.001). The table compares baseline and 4-week FGF23, α-klotho, and VDBP levels in the control and intervention arms, and no significant differences were noted between the groups who received DRI vs. high dose cholecalciferol.

Conclusion

Cholecalciferol supplementation of 4000 IU/day in children with CKD was not associated with significant differences in FGF23, α-klotho, or VDBP levels compared to children who received only the DRI.

Mean (SD)400 IU4000 IUp-value
C-terminal FGF23, B (RU/ml)44.5 (32.8)46.5 (38.6)0.76
C-terminal FGF23, W (RU/ml)39.5 (26.9)45.3 (30.1)0.61
Intact FGF23, B (pg/ml)19.1 (14.4)18.7 (12.9)0.93
Intact FGF23, W (pg/ml)20.3 (12.9)19.6 (11.9)0.89
α-klotho, B (pg/ml)3,321.9 (4,4221.82)1.944.7 (1,257.1)0.22
α-klotho, W (pg/ml)3,340.4 (5,146.3)1,959.4 (1,598.1)0.36
VDBP, B (ng/ml)327,437.5 (58,516.6)332,400 (86,243.1)0.78
VDBP, W (ng/ml)328,666.7 (72,235.4)352,661.5 (74,871.8)0.40

B=baseline W=4 week