Serum Intact and Total Fibroblast Growth Factor 23 Levels and Iron-related Parameters in Hemodialysis Patients

Abstract

Objective: Fibroblast growth factor (FGF)23 suppresses erythropoiesis and is implicated in iron metabolism. It was investigated whether high levels of FGF23 was associated with hepcidin levels of iron metabolism markers in hemodialysis patients. Methods: The serum hepcidin, erythroferrone, and intact-FGF23 or total-FGF23 level as well as iron-related parameters at pre-dialysis in 70 hemodialysis (HD) patients was measured and performed a regression analysis. Results: Each measurement for FGF23, including the intact-/total-FGF23 ratio, correlated strongly with both serum inorganic phosphate and calcium-phosphate product concentrations. Serum hepcidin levels showed a positive correlation with TSAT or serum ferritin concentration. In addition, a negative correlation was found between serum of hepcidin and erythroferrone levels, but no correlation was found between FGF23-related measurements and serum hepcidin levels. Both serum FGF23 levels and erythroferrone levels correlated with erythropoietin-stimulating agent treatment. Conclusion: It was strongly suggested that both serum phosphate concentrations and calcium-phosphate products were associated with FGF23 production in HD patients. As previously reported, the association between hepcidin and iron metabolism markers was reconfirmed, but a simple linear relationship between hepcidin and FGF23 was not observed even after adjusting FGF23. However, a significant negative correlation between erythroferrone and serum hepcidin levels was confirmed in HD patients.