Serum intact FGF23 associate with left ventricular mass, hypertrophy and geometry in an elderly population.

Fibroblast growth factor-23 (FGF23) is a hormonal regulator of circulating phosphate and vitamin D levels. Serum FGF23 is elevated in chronic kidney disease (CKD) and is a prognostic marker of poor outcomes, such as faster CKD progression and increased mortality in hemodialysis patients. Despite the high prevalence of cardiovascular disease in CKD, the relation between circulating FGF23 and cardiovascular risk factors, both in CKD and in the community, has not been studied in detail. We evaluated the relation between FGF23, left ventricular mass index (LVMI), hypertrophy (LVH) and LV geometry, employing the community-based PIVUS cohort. In total, 795 Swedish men and women aged 70 were included of which 164 had an age-adjusted diminished renal function (estimated glomerular filtration rate<60mL/min/1.73m(2)). FGF23 was positively associated with LVMI (beta=0.11, CI 0.01-0.18), with increased odds for the presence of LVH (OR 1.28, CI 1.09-1.51) and for concentric hypertrophy (OR 1.45, CI 1.19-1.77) in the whole population. All associations were stronger in subjects with eGFR<60mL/min/1.73m(2) (beta=0.30, CI 0.15-0.46 for LVMI; OR 1.86, CI 1.30-2.67 for the presence of LVH; OR 1.83, CI 1.17-2.85 and OR 1.87, CI 1.08-3.22 for concentric and eccentric hypertrophy, respectively). The results were essentially unaltered in multivariate models. In summary, elevated serum FGF23 levels, even within the normal range, are associated with increased LVMI and increased risk for the presence of LVH in elderly subjects. Additional longitudinal studies that evaluate the predictive power of FGF23 and whether FGF23 has additional clinical applications are needed.