FIBROBLAST GROWTH FACTOR-23 AND PARATHYROID HORMONE PREDICT THE EXTENT OF AORTIC VALVE CALCIFICATIONS IN PATIENTS WITH CHRONIC KIDNEY DISEASE NOT ON DIALYSIS

INTRODUCTION AND AIMS: Cardiac valve calcification (CVC) are commonly present in patients on dialysis and dependent on deranged mineral metabolism. Few data are available in patients with chronic kidney disease not on dialysis (CKD-ND patients). In this study association between CVC and levels of PTH, phosphorus, calcium, 25-OH vitamin D, FGF-23, Klotho, C-Reactive protein was contemporaneously evaluated in CKD-ND patients. METHODS: This is a multicenter study performed in consecutive patients referring to five Nephrology Clinics. Inclusion criteria were: age>18 years, CKD stage 3-4, presence of aortic or mitral valve calcification. Clinical examination, routine biochemistry measurements, extent of mitral (MVC) and aortic valve calcification (AVC) by echocardiography were performed. RESULTS: One hundred patients met inclusion criteria and underwent final evaluation. AVC was found in n.100 patients; MVC was found in n.96 patients. In univariate analysis, no association was found between MVC and e-GFR, serum phosphorus , PTH, FGF-23, Klotho, 25-OH vitamin D, 24/h phosphaturia, CRP. AVC was positively associated with PTH (r2 = 0.212; p=0.034), FGF-23 (r2 = 0.272; p=0.006), and negatively with Klotho (r2 = - 0.208; p=0.038). In multivariable analysis FGF-23 and PTH were significantly associated with AVC score. CONCLUSIONS: FGF-23 and PTH were associated to AVC extent of CKD-ND patients. No association was found with other variables of interest. These data indicate that FGF-23 and PTH play a direct action on AVC calcification; the role of FGF-23 and PTH was independent from markers of mineral metabolism and inflammation. These data may come into the still open debate on the usefulness of FGF-23 assay in routine clinical care of CKD-ND as part of cardiovascular risk stratification. Session: Poster Session: Chronic Kidney Disease. Bone disease