Fibroblast growth factor 23 in patients with acute dyspnea: Data from the Akershus Cardiac Examination (ACE) 2 Study

Circulating fibroblast growth factor 23 (FGF23) concentrations have been linked to left ventricular remodeling and unfavorable cardiovascular outcomes, but whether FGF23 is associated with heart failure (HF) diagnosis and outcome in unselected patients with dyspnea is unknown. Accordingly, we assessed the diagnostic and prognostic properties of FGF23 in patients presenting to the emergency department with acute dyspnea.

FGF23 was measured in 314 patients admitted with acute dyspnea and the diagnostic and prognostic merit was compared to that of N-terminal pro-B-type natriuretic peptide (NT-proBNP). The diagnosis of acute HF was adjudicated by two independent physicians. Circulating FGF23 concentrations on hospital admission were higher in patients with acute HF vs. patients with non-HF related dyspnea: median 3.60 (IQR 1.24-8.77) vs. 1.00 (0.43-2.20) pmol/L; P<0.001. The receiver-operating statistics area under the curve for acute HF diagnosis was 0.750 (0.699-0.797) for FGF23 and 0.853 (0.809-0.890) for NT-proBNP. Adjusting for clinical risk indices and cardiac biomarkers in multivariate Cox regression analysis, admission FGF23 concentrations were associated with mortality in the total study population (hazard ratio [HR] per 1 SD in _lnFGF23 1.74 [1.40-2.16]). FGF23 also reclassified patients into their correct risk strata on top of clinical variables significantly associated with outcomes in the total cohort (net reclassification index 0.386 [0.161-0.612]). In patients with acute HF, both admission FGF23 and NT-proBNP concentrations were associated with mortality.

Circulating FGF23 concentrations provide incremental prognostic information to established risk indices in patients with acute dyspnea, but do not improve diagnostic accuracy over NT-proBNP measurements.