LAUSR

To the Editor: In a recent study, Sharma et al. reported an association between higher levels of fibroblast growth factor 23 (FGF-23) and left ventricular (LV) diastolic dysfunction in 47 end-stage renal disease (ESRD) patients receiving hemodialysis. Fibroblast growth factor 23 requires Klotho protein as a coreceptor to bind FGF receptors and to exert its biological effects. Moreover, Klotho deficiency contributes to chronic kidney disease (CKD) progression and development of cardiovascular diseases in patients with advanced CKD. We studied an association of FGF-23 and Klotho levels with LV hypertrophy and diastolic function in 51 patients with CKD G4-5D patients (median age, 48 years; 27 male patients). In all, 26 patients were treated with hemodialysis. Serum FGF-23 and Klotho levels were measured by enzyme-linked immunosorbent assay. Left ventricular diastolic function was evaluated using Doppler echocardiographic analysis. Characteristics of the study cohort stratified by quartiles of FGF-23 levels are shown in Table 1. As expected, serum Klotho levels were decreased in patients with higher FGF-23 levels. Serum FGF-23 and Klotho levels significantly correlated with LV diastolic dysfunction (r 1⁄4 0.469, P 1⁄4 0.002, and r 1⁄4 0.501, P 1⁄4 0.001, respectively). According to multivariate analysis,