Purpose: Cardiovascular events are the major reasons for mortality in haemodialysis patients. Fibroblast growth factor 23 (FGF23), Klotho protein and G-395A Klotho gene polymorphism have been associated with effects on the cardiovascular system. Our study investigates the interrelationship between Klotho protein gene variations, mineral-bone metabolism and left ventricular hypertrophy in patients undergoing chronic haemodialysis programme.
Materials and methods: Patients (n = 142) were genotyped for G-395A Klotho gene. Components of mineral-bone metabolism, classical and non-classical (FGF23, Klotho and vitamin D) as well as echocardiographic examination were determined. Predictive models were designed to determine the significance of Klotho gene variations and mineral-bone metabolism components for left ventricle hypertrophy (LVH).
Results: A-allele carriers were longer on haemodialysis (p = 0.033), and had higher phosphorus levels (p = 0.016) while the level of Klotho protein was significantly lower (p = 0.001) compared to non-A-allele carriers. The best gains were achieved upon addition of allele A, and all three new markers; the AUC made significant improvement from 0.596 to 0.806 (p < 0.001), and improved net reclassification for 82.1% (95% CI 42.9-121.3%).
Conclusions: The genetic background of A-allele carriers of the G-395A Klotho gene polymorphism increases the susceptibility patients to haemodialysis. A-allele carriers are at a higher risk for the development of cardiovascular complications. The addition of non-classical to classical mineral metabolism components improves prediction power to LVH.
Keywords: FGF23; Haemodialysis; Klotho; Klotho gene polymorphism; LVH; Predictive models.