FGF-23 levels are associated with vascular calcification, but not with atherosclerosis, in hemodialysis patients.

PURPOSE: High fibroblast growth factor-23 (FGF-23) levels are associated with mortality and cardiovascular events in patients with chronic kidney disease. The aim of this cross-sectional study was to investigate the relationship between plasma FGF-23 levels and coronary artery calcification and carotid artery intima-media thickness (CA-IMT) in hemodialysis (HD) patients.

METHODS: In this cross-sectional study, plasma intact FGF-23 levels were measured in 229 patients who underwent coronary artery calcification scores (CACs) determined by multi-slice computerized tomography and CA-IMT assessed by using high-resolution color Doppler ultrasonography.

RESULTS: Median FGF-23 was 53.5 pg/ml (IQR 30.8-249.5). Median CACs was 98 (IQR 0-531), and the frequency of patients with severe calcification (CACs > 400) was 28.8%; 27.5% of cases had no calcification. Mean CA-IMT was 0.78 ± 0.20 mm, and the presence of carotid plaques was 51% with a mean length 2.1 mm. FGF-23 level was positively correlated with serum calcium (r = 0.337, p < 0.001), phosphate (r = 0.397, p < 0.001) and CACs (r = 0.218, p = 0.001). Neither CA-IMT nor the presence of carotid artery plaques correlated with FGF-23 levels. In adjusted ordinal regression analysis, FGF-23 level was an independent predictor for severe CACs together with age, gender, presence of diabetes, time on dialysis and CA-IMT (model r(2) = 0.44, p < 0.001). As a novel finding, the mean CACs was markedly higher in patients with FGF-23 level above median regardless of phosphate levels (p = 0.03).

CONCLUSIONS: In HD patients, plasma FGF-23 level is superior to phosphate in the prediction of coronary artery calcification. However, FGF-23 is not associated with carotid artery atherosclerosis in HD patients.