THE RELATIONSHIP BETWEEN ARTERIAL STIFNESS AND 25-(OH) VITAMIN D, FGF 23 IN MAINTENANCE HEMODIALYSIS PATIENTS

PURPOSE: Vascular calcification (VC) is highly prevalent in maintenance hemodialysis (MHD) population and increasing evidence indicates that abnormalities in mineral metabolism are closely associated with VC and increased mortality in chronic kidney disease (CKD) patients. In our study, we hypothesized that high FGF-23 and low endogeneous vitamin D levels might be a result of high calcium load and aimed to determine the relationship between 25-hydroxy vitamin D levels and arterial stiffness in CKD patients. MATERIALS AND METHODS: One hundred and seventeen patients who were receiving MHD 3 times a week for at least 24 months were selected and followed up for 12 months.We analysed the influence of one years’ cumulative calcium and theraupetic vitamin D (paricalcitol and calcitriol) intake, and serum FGF-23 level on 25(OH)D3 levels and the impacts of these parameters on the change in annual PWV measurement results in MHD patients. RESULTS: Elementary calcium dose was significantly higher in vitamin D insufficiency group than compared to control group (p=0.014). Seum level of FGF-23 were positively correlated with duration of HD (p=0.001), mean PTH (p=0.001), mean P (p=0.009) and mean CaxP (p=0.006). Baseline PWV measurement were similar between two groups however patients in insufficiency group had higher 12th month PWV measurements compared to control group (p=0.034). CONCLUSION: Calcium could increase serum FGF23 levels by indeterminate mechanisms independently of serum phosphate level. Elevated FGF-23 levels was found to be insulting a decline in vitamin D levels which may cause VC and stiffening of the arteries and resulting higher PWV measurements.