Baseline FGF23 is associated with cardiovascular outcome in incident PD patients

Abstract

Introduction: Fibroblast growth factor 23 (FGF23) is a phosphate regulating protein. Several studies demonstrated that elevated FGF23 is independently associated with mortality for early stage chronic kidney disease and incident hemodialysis (HD) patients. However, little is known about the significance of elevated FGF23 in peritoneal dialysis (PD) patients. Here, we analyzed the association of baseline FGF23 with cardiovascular (CV) events, all-cause mortality, residual renal function (RRF), and CV parameters.

Methods: The present study is a single-center, retrospective study. Patients who started PD at Seoul National University Hospital between Jan, 2005 and July, 2011 and whose baseline serum samples were available were enrolled. C-terminal FGF23 was measured. Subjects were divided into two groups

lower 2 tertiles (FGF23 ≤ 119.0 RU/mL) and top tertile (FGF23 > 119.0 RU/mL). The primary outcome was time-to-the fatal or non-fatal CV events. In the subgroup analysis, the associations of FGF23 with aortic stiffness or with vascular calcification were analyzed.

Results: A total of 205 incident PD patients were analyzed. Mean duration of follow-up was 41.6 ± 20.0 months. The baseline median FGF23 level was 78.6 RU/ml (IQR, 34.1-155.0). At baseline, subjects in the higher FGF23 group were younger, and had a lower RRF, lower prevalence of diabetes mellitus (DM), and cerebrovascular disease. During follow-up, 22 of the 205 patients (10.7%) reached primary outcome. After adjustment to the age, DM, pre-existing coronary artery disease, cerebrovascular disease, congestive heart failure, and left ventricular mass index, higher FGF23 group exhibited significantly higher risk of primary outcome, compared with the lower group (HR, 2.54

95% CI, 1.05-6.12

P = 0.045). There were no significant differences in all-cause mortality and development of anuria between the two FGF23 groups. In the subgroup analysis, FGF23 groups were not associated with pulse wave velocity and abdominal aortic calcification score calculated by lateral lumbar radiograph.

Conclusions: Elevated FGF23 is associated with higher risk of adverse CV outcome for incident PD patients.