Association of serum FGF23 with abdominal aortic calcification and outcomes in maintenance hemodialysis patients

Objective To explore the association of fibroblast growth factor-23 (FGF23) with abdominal aortic calcification(AAC) and adverse outcomes in maintenance hemodialysis patients. Methods One hundred and fourteen cases of MHD patients were collected prospectively. Serum intact FGF23 was detected by ELISA. Abdomen lateral plain was used as a criteria to determine the abdominal aortic calcification and the abdominal aortic calcification score was counted. Logistic regression analysis was used to determine the risk factors of AAC. Kaplan-Meier analysis was applied to compare the survival rate among different groups and COX regression analysis was used to determine the association of FGF23 and mortality in MHD patients. Results Seventy-six patients present abdominal aortic calcification. The median of AACS was 4.0(0.0, 11.0). The median level of FGF23 was 7277.4(2535.0, 9990.8) pg/ml. The median follow-up duration was 72.0(67.8, 72.8) months. During the follow-up, 22 patients (19.3%) died of all-cause death and 17 cases (14.9%) died of cardiovascular diseases. Serum FGF23 level was positively correlated with AAC (r=0.285, P=0.002). Logistic regression analysis showed that longer age (OR=1.059, 95%CI: 1.020-1.100, P=0.003) and dialysis vintage (OR=1.009, 95%CI 1.000-1.017, P=0.039), smoking history (OR=3.010, 95%CI 1.177-7.696, P=0.021) and higher FGF23 level(OR=2.831, 95%CI 1.010-7.937, P=0.048) were independent risk factors of moderate to severe AAC in MHD patients. Kaplan-Meier survival curves showed that the patients with AACS≥5 had significantly higher all-cause mortality(P=0.028) and CVD mortality (P=0.035) than those with AACS<5. However, the Kaplan-Meier analysis showed no significant difference regarding the level of serum FGF23 with the all-cause and CVD mortality. Cox regression demonstrated that FGF23 was not associated with increased mortality risk, neither in crude nor in multivariate adjusted models. Conclusions Abdominal aortic calcification had a high prevalence in MHD patients. The all-cause and CVD mortality was higher in patients with moderate to severe AAC. FGF23 was an independent risk factor of moderate to severe AAC, but it can't yet be a predictor for the all-cause and CVD mortality of MHD patients. Key words: Renal dialysis; Fibroblast growth factor; Calcinosis; Mortality; Cardiovascular disease mortality