Inorganic phosphate and FGF-23 predict outcome in stable systolic heart failure

Eur J Clin Invest 2012; 42 (6): 649656 Abstract Background Recent studies show associations between inorganic phosphate and risk of heart failure in the general population as well as between fibroblast growth factor 23 (FGF-23) and outcome in coronary heart disease. This study was carried out to assess whether circulating levels of inorganic phosphate and FGF-23, a new central hormone in mineral bone metabolism, predict outcome in systolic heart failure. Materials and methods Ninety-nine consecutive outpatients with systolic heart failure were enrolled. Mean (SD) age was 61 years (11), mean left ventricular ejection fraction (LVEF) was 33% (10), 82 patients were men, median estimated creatinine clearance was 83 mL/min (Q1Q3 58106), median NTproBNP level was 803 pg/mL (Q1Q3 4042757), median inorganic phosphate was 1.12 mM (Q1Q3 1.021.22), median FGF-23 was 39.02 pg/mL (Q1Q3 32.4555.86) and median follow-up was 35 months. Associations between inorganic phosphate, FGF-23 and endpoints were assessed using Cox regression analyses. Results Inorganic phosphate and FGF-23 levels were significantly higher (P < 0.001 and P = 0.009) in patients reaching the combined endpoint of cardiac hospitalization or death. FGF-23 (ln) predicted all-cause mortality (hazard ratio (HR) 5.042, P = 0.032) in a model adjusted for age, gender, estimated creatinine clearance, LVEF, New York Heart Association (NYHA) stage and NTproBNP level. Inorganic phosphate predicted heart failure hospitalization (HR 26.944, P = 0.021), cardiac hospitalization (HR 16.016, P = 0.017) and the combined endpoint (HR 13.294, P = 0.015) in models adjusted for the same co-variables. Conclusion The results of this study demonstrate the independent prognostic value of inorganic phosphate and FGF-23 in heart failure even in the context of established risk markers.