Background-Fibroblast growth factor 23 (FGF-23) is a phosphorus-regulating hormone. In chronic kidney disease (CKD), circulating FGF-23 levels are markedly elevated and independently associated with mortality. Left ventricular hypertrophy and coronary artery calcification are potent risk factors for mortality in CKD, and FGFs have been implicated in the pathogenesis of both myocardial hypertrophy and atherosclerosis. We conducted a cross-sectional study to test the hypothesis that elevated FGF-23 concentrations are associated with left ventricular hypertrophy and coronary artery calcification in patients with CKD. Methods and Results-In this study, 162 subjects with CKD underwent echocardiograms and computed tomography scans to assess left ventricular mass index and coronary artery calcification; echocardiograms also were obtained in 58 subjects without CKD. In multivariable-adjusted regression analyses in the overall sample, increased log FGF-23 concentrations were independently associated with increased left ventricular mass index (5% increase per 1-SD increase in log FGF-23; Pϭ0.01) and risk of left ventricular hypertrophy (odds ratio per 1-SD increase in log FGF-23, 2.1; 95% confidence interval, 1.03 to 4.2). These associations strengthened in analyses restricted to the CKD subjects (11% increase in left ventricular mass index per 1-SD increase in log FGF-23; Pϭ0.01; odds ratio of left ventricular hypertrophy per 1-SD increase in log FGF-23, 2.3; 95% confidence interval, 1.2 to 4.2). Although the highest tertile of FGF-23 was associated with a 2.4-fold increased risk of coronary artery calcification Ն100 versus Ͻ100 U compared with the lowest tertile (95% confidence interval, 1.1 to 5.5), the association was no longer significant after multivariable adjustment. Conclusions-FGF-

ISK STRATIFICATION FOR HEART failure (HF) in older adults involves unique clinical challenges. Elderly individuals comprise the largest subgroup of patients hospitalized for HF, accounting for 80% of the more than 1.1 million US admissions per year. 1,2 Once diagnosed with HF, older patients respond less well to guideline-based therapy than their younger counterparts, are more likely to require readmission, and are at higher risk for death. 2-4 Furthermore, prediction models based on traditional cardiovascular risk factors are less adept at identifying cardiovascular risk in older adults compared with younger populations. 5 Blood-based biomarkers, including C-reactive protein (CRP), natriuretic peptides, and troponins, have been advocated as adjuncts to clinical risk factors to identify community-dwelling older patients at high risk for adverse cardiovascular outcomes, but studies examining the additive prognostic value of these markers have reported inconsistent results.