Serum Fibroblast Growth Factor-23 Levels in Chronic Haemodialysis Patients

Background: Fibroblast Growth factor-23 (FGF 23) is a circulating factor that regulates renal reabsorption of inorganic phosphate. Serum FGF 23 level is increased in chronic kidney disease (CKD) patients as a compensatory mechanism to hyperphosphatemia. FGF 23 directly signals in the parathyroid glands and predicts future secondary hyperparathyroidism in dialysis patients. We examined the relationship between FGF 23 and serum calcium, phosphate, 1, 25 (OH)2 D3, and PTH levels in haemodialysis patients. Methods: FGF 23 and above mentioned parameters were measured in 50 chronic haemodialysis patients. We analysed the correlation between FGF 23 and all other parameters using Pearson correlation coefficient and multiple regression analysis. Results: FGF 23 was significantly increased in haemodialysis patients compared to healthy controls (1525.48±373.57 Vs. 37.70±9.71pg/mL, p 0.0001). 1, 25 (OH)2 D3 levels were significantly reduced whereas PTH levels were significantly higher in dialysis patients compared to controls (59.46±12.13 Vs. 85.73±12.14pg/mL, p 0.05 and 343.21±436.72 Vs. 52.12± 10.67pg/mL, p 0.05 respectively). Mean serum phosphate was 7.14±3.05mg/dl. There was significant negative correlation between log FGF 23 and 1, 25 (OH)2 D3 (r=-0.375, p=0.009) and significant positive correlation between log FGF 23 and log PTH values (r=0.287,p=0.041). Log PTH and 1, 25 (OH)2 D3 values were independent predictors of log FGF 23 on multiple regression analysis (p=0.037 and 0.009 respectively). Conclusions: Our results revealed marked increase in FGF 23 levels in haemodialysis patients. PTH and vit D3 were independent predictors of FGF 23 in the study group. Serum phosphate did not correlate or predict FGF 23 level despite the high prevalence of hyperphosphatemia in the study group.