Intravenous calcitriol therapy increases serum concentrations of fibroblast growth factor-23 in dialysis patients with secondary hyperparathyroidism

Nephron Clin Pract. 2005;101(2):c94-9. doi: 10.1159/000086347. Epub 2005 Jun 14.

Abstract

Background/aims: Fibroblast growth factor-23 (FGF-23) is a recently discovered phosphaturic factor. Although increased levels of serum FGF-23 have been reported in dialysis patients, the role of high FGF-23 levels remains unclear. Since FGF-23 is associated also with vitamin D metabolism, we examined the changes of serum FGF-23 levels in chronic dialysis patients treated with intravenous calcitriol therapy.

Methods: Thirty patients with severe secondary hyperparathyroidism were treated with intravenous calcitriol (0.5-1.0 microg) two or three times per week for 6 months. The changes of serum levels of calcium, phosphate, intact PTH, and FGF-23 were evaluated.

Results: Baseline serum FGF-23 levels were markedly high. By intravenous calcitriol therapy, intact PTH levels decreased effectively in the first month (p < 0.001). In contrast, FGF-23 levels increased gradually during the study period (p = 0.027). The Delta serum FGF-23 level was significantly correlated with the total doses of calcitriol injected intravenously in 6 months in patients with refractory secondary hyperparathyroidism (R2 = 0.147; p = 0.036).

Conclusions: Intravenous calcitriol decreased serum intact PTH level and increased serum FGF-23 levels significantly. Extremely high levels of serum FGF-23 in these patients may be attributed, at least in part, to the cumulative dose of vitamin D.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcitriol / administration & dosage*
  • Female
  • Fibroblast Growth Factors / blood*
  • Humans
  • Hyperparathyroidism, Secondary / blood*
  • Hyperparathyroidism, Secondary / drug therapy*
  • Injections, Intravenous
  • Male
  • Middle Aged
  • Renal Dialysis*

Substances

  • Fibroblast Growth Factors
  • fibroblast growth factor 23
  • Calcitriol