Vitamin K Status of Patients Undergoing Hemodialysis: Insights from a Cross-Sectional Study

Abstract

(1) Background: Vitamin K deficiency is a common feature of chronic kidney disease (CKD), leading to impaired bone quality and an increased risk of vascular calcifications. A method to indirectly assess the vitamin K status is measuring the blood level of vitamin K-dependent proteins (VKDP): osteocalcin (OC) and matrix GLA protein (MGP). The aim of this study is to correlate the level of total OC and inactive MGP (dp-uc MGP) with markers of CKD mineral bone disorder (CKD-MBD). (2) Methods: We conducted a single-center cross-sectional study that included 45 CKD G5D patients and measured their blood biochemistry, complete blood count and total osteocalcin and dp-uc MGP contents. (3) Results: We found a strong, statistically significant correlation of the total OC with the markers of CKD-MBD, such as: iPTH, serum calcium and serum phosphorus, and a strong, indirect statistically significant correlation with abdominal circumference. There was also a statistically significant correlation of dp-uc MGP with the markers of inflammation (CRP). Higher levels of dp-uc MGP were found in the patients treated with vitamin K antagonists, non-calcium-based phosphate binders and the vitamin D receptor activator, paricalcitol. (4) Conclusions: In our study, we found that when it is measured indirectly using VKDP levels, vitamin K deficiency is associated with CKD-MBD. Certain widely used medications such as phosphate binders reduce vitamin K absorption, supplementary vitamin D increases vitamin K requirements, and also vitamin K antagonists influence the blood level of VKDPs.