Vitamin K_2 Alters Bone Metabolism Markers in Hemodialysis Patients with a Low Serum Parathyroid Hormone Level

Background: A low level of intact parathyroid hormone (PTH) is an indicator of adynamic bone disease in hemodialysis patients, and is associated with a significant increase of all-cause mortality. Thus, effective treatment for adynamic bone disease is required. We previously investigated the effect of vitamin K2 on adynamic bone disease. In this study, we assessed the efficacy of oral vitamin K2 in a controlled trial. Methods: Forty hemodialysis patients with low intact PTH levels (2 group receiving oral menatetrenone (45 mg/day) for 1 year and a control group without vitamin K2. Venous blood samples were collected at baseline and during the study for measurement of bone metabolism parameters. Results: Thirty-three patients completed follow-up. There was a significant increase of the serum intact osteocalcin level after 1 month of vitamin K2 administration. Serum levels of intact PTH, bone alkaline phosphatase, and cross-linked N-terminal telopeptide of type I collagen increased significantly after 12 months in the vitamin K2 group. The serum osteoprotegerin level was decreased after 12 months in the vitamin K2 group, but the change was not significant. Conclusion: Vitamin K2 therapy improves bone remodeling in hemodialysis patients with a low intact PTH level.