Serum fibroblast growth factor-23 levels in chronic haemodialysis patients

Background  Fibroblast growth factor-23 (FGF23) is a circulating factor that regulates renal reabsorption of inorganic phosphate. Serum FGF23 level is increased in chronic kidney disease (CKD) patients as a compensatory mechanism to hyperphosphataemia. FGF23 directly signals in the parathyroid glands and can be used to predict future secondary hyperparathyroidism in dialysis patients. We examined the relationship between FGF23 and serum calcium, phosphate, 1,25(OH)₂D₃, and PTH levels in haemodialysis patients. Methods  FGF23 and the above mentioned characteristics were measured in 50 chronic haemodialysis patients. We analysed the correlation between FGF23 and the other characteristics by using the Pearson correlation coefficient and multiple regression analysis. Results  FGF23 was significantly increased in haemodialysis patients compared with healthy controls (1525 ± 373 vs. 37 ± 9 pg/ml, P < 0.0001). There was a significant negative correlation between log FGF23 and 1,25(OH)₂D₃ (R = −0.375, P = 0.009) and a significant positive correlation between log FGF23 and log PTH values (R = 0.287, P = 0.041). In multiple regression analysis log PTH and 1,25(OH)₂D₃ values were independent predictors of log FGF23 (P = 0.037 and 0.009, respectively). Conclusions  Our results revealed a marked increase in FGF23 levels in haemodialysis patients. PTH and vitamin D3 were independent predictors of FGF23 in the study group. Serum phosphate did not correlate with or predict FGF23 level despite the high prevalence of hyperphosphataemia in the study group.