Effect of phosphate binder therapy on FGF-23 levels in dialysis patients

Abstract

Introduction. Fibroblast growth factor type 23 (FGF-23) inhibits phosphate reabsorption and vitamin D hormone synthesis in the kidneys. There is a known relationship between FGF-23 levels and serum phosphate, as well as a direct correlation between hyperphosphatemia and the risk of cardiovascular events.Aim. To evaluate associations between serum FGF-23 levels and bone and mineral metabolism in patients on renal replacement therapy (RRT) with hemo- and peritoneal dialysis, receiving and not receiving phosphate binders.Materials and methods. The study included 65 patients, of which 43 received maintenance hemodialysis tratment (HD), and 22 – peritoneal dialysis (PD). The control group consisted of 28 healthy volunteers.Results. The increase in the concentration of FGF-23 in the blood serum in patients on maintenance HD correlated with the vintage of dialysis treatment (rs = 0,765; p = 0,04). The positive correlation was found between the serum concentrations of FGF-23 and inorganic phosphorus (rs = 0,54; p = 0,03). The serum level of FGF-23 positively correlated with the serum PTH level (rs = 0,5; p = 0,01). In patients receiving sevelamer carbonate levels of FGF-23 was lower, than in control group (12.4 ± 5.9, and 23 ± 7.3, respectively; p = 0.003), as well as PTH (110 ± 27 ng/mL, and 340 ± 15, respectively; p = 0.01).Conclusions. The level of FGF-23 in dialysis patients directly correlated with the serum level of PTH and “dialysis vintage”. The use of phosphate binders, in particular sevelamer carbonate, positively affects the expression of FGF-23 and PTH in dialysis patients.