Fibroblast growth factor is associated to left ventricular mass index, anemia and low values of transferrin saturation

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 (LVH) is a potent risk factor for mortality in CKD, and FGFs have been implicated in the pathogenesis of myocardial hypertrophy. In addition, the effect of anemia on CV disease and LVH is well known in CKD. A relation between iron and FGF-23 metabolism is mentioned in a few studies. The aim of this study was to test the association of FGF-23 levels with echocardiographic (ECHO) and iron parameters in peritoneal dialysis patients (PD). Methods: In this cross-sectional study, 61 subjects with PD (29 women and 32 men, mean age: 46.9 +/- 13.3 years, mean PD vintage: 69.5 +/- 39 months) underwent echocardiograms to assess left ventricular mass index (LVMI). Medical treatments and average values of the basic laboratory results of the last 6 months for all patients were recorded. Serum FGF-23 concentrations were measured using intact FGF-23 (iFGF-23) human enzyme-linked immunosorbent assay (ELISA) kit. According to the median levels of serum FGF-23 the patients were grouped into two (FGF-23 high and low groups). Results: Significant positive correlation was recorded between serum FGF-23 levels and LVMI (P = 0.023). There was also significant difference in terms of hemoglobin (12.1 +/- 2 versus 11.0 +/- 2, P = 0.017), transferrin saturation (TSAT) (24.9 +/- 16.8 versus 19.5 +/- 10.8, P = 0.042) between low and high FGF-23 group. Also in linear regression analysis the negative relation between FGF-23 and hemoglobin is persisted (r = 0.199, P = 0.045). Conclusions: FGF-23 is associated with LVMI, anemia and low TSAT in patients with PD. Whether increased FGF-23 is a marker or a potential mechanism of myocardial hypertrophy and anemia in patients with end-stage renal disease (ESRD) requires further study. (C) 2015 Sociedad Espanola de Nefrologia. Published by Elsevier Espana, S.L.U.