The effect of vitamin K2 supplementation on vascular calcification in haemodialysis patients: a 1-year follow-up randomized trial.

Abstract

Vascular calcification (VC) is an independent risk factor for cardiovascular disease in hemodialysis patients while Matrix GLA protein (MGP) is one of the most potent inhibitors of VC and its activation is vitamin K dependent. The aim of this study is to investigate the role of oral vitamin K2 supplementation in the prevention of VC progression in haemodialysis patients. We conducted a prospective randomized interventional study in patients on hemodialysis. Patients were randomly assigned to either receiving orally 200μgr of vitamin K2 (vitamin K2/MK-7, Solgar) every day for 1year or no treatment. Uncarboxylated MGP (uc-MGP) concentrations were quantified using ELISA at randomization, at 3 and at 12months. Aortic calcification was evaluated using Agatston score after an abdominal computed tomography scan that was performed at the beginning and at 12months of follow-up. There were 102 patients that were randomized. After 1year of follow-up, 22 patients from the vitamin K2 group and 30 patients from the control group were included in the analysis. After 3months of treatment, uc-MGP values remained unchanged in the vitK2 group but after 1year were reduced by 47% (p = 0.005). Furthermore, uc-MGP at 1year was increased by 12% in the control group. At 1year, vitK2 group had significantly lower values of uc-MGP in comparison to controls (p = 0.03). Agatston score was increased significantly both in vitamin K2 and control group at 1year with no difference between groups. Oral administration of vitamin K2 in patients on haemodialysis reduced serum uc-MGP levels but did not have an effect in the progression of aortic calcification.