Vitamin K2 supplementation and the progression of abdominal aortic calcification in dialysis patients

Objectives: Vascular calcification is common in patients with advanced chronic kidney disease (CKD) and contributes to cardiovascular disease. Accumulating evidence indicates that CKD patients often acquire subclinical vitamin K deficiency, which is associated with vascular calcification. Methods: This prospective, randomized, parallel group, multicenter trial (UMINID000011490) will include 200 dialysis patients in an open-label, two-arm design. After baseline computed tomography of the abdominal aorta, patients will be randomized to two groups that will either (1) continue receiving standard care or (2) receive additional oral supplementation with menatetrenone (45 mg/day). The treatment duration will be 24 months, and the computed tomography scan will be repeated after 12 and 24 months. The primary endpoint is the progression of abdominal aortic calcification, which is calculated as absolute changes based on the Agatston score. The secondary endpoints are the decrease in bone mineral density (measured by dual-energy X-ray absorptiometry), the biomarkers associated with vitamin K, vitamin K intake (evaluated by the food frequency questionnaire), and the biomarkers associated with vascular calcification. Conclusions: This study aims to confirm whether vitamin K has inhibitory effects on calcification that can be clinically determined. Trial registration: UMINID000011490.