25-Hydroxyvitamin D Levels and Vascular Calcification in Predialysis and Dialysis Patients with Chronic Kidney Disease

BACKGROUND/AIMS: The role of vitamin D in the process of vascular calcification is unclear in patients with chronic kidney disease. We investigated whether serum 25-hydroxyvitamin D [25(OH)D] is associated with vascular calcification in predialysis and dialysis patients. METHODS: We included 86 predialysis and 139 dialysis patients. The simple vascular calcification score (SVCS) was evaluated by examining plain X-rays of the pelvis and hands as described previously. The carotid-to-femoral pulse wave velocity (CF-PWV) was assessed with a commercially available device. RESULTS: We found a high prevalence of vitamin D deficiency in our population (78.2%). Vascular calcification was present in 46.2% of all patients. Higher calcification (SVCS >3) was significantly associated with lower 25(OH)D levels in predialysis and dialysis patients. Multiple logistic regression analysis for SVCS >3 showed that 25(OH)D levels were negative independent predictors in predialysis (OR: 0.781; 95% CI: 0.623-0.908, p = 0.019) and dialysis patients (OR: 0.805; 95% CI: 0.749-0.853, p = 0.009). Lower 25(OH)D levels were associated with higher CF-PWV in predialysis patients, but this inverse relationship was no longer present in multivariate analysis. CONCLUSION: We showed an independent relationship between low serum 25(OH)D levels and vascular calcification in both predialysis and dialysis patients.