Vitamin K₂ 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 (<100 pg/ml) were randomly divided into two groups, which were a vitamin K₂ 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.