Osteocalcin and vascular calcification in hemodialysis patients: an observational cohort study.

BACKGROUND: Vascular calcification contributes to morbidity and mortality in patients with ESRD on maintenance hemodialysis.

AIMS: To study the relationship between osteocalcin and vascular calcification.

METHODS: 160 patients with ESRD on maintenance hemodialysis and 60 age-and sex-matched healthy controls were recruited. Serum vitamin K2 and osteocalcin both intact and undercarboxylated were measured. Transthoracic echocardiography was done for valvular calcification and thickening, and carotid duplex was done for carotid intimal medial calcification and thickening.

RESULTS: Hemodialysis patients have higher median serum vitamin K2 (p < 0.001), higher undercarboxylated osteocalcin (p < 0.001). Only older age, duration of hypertension, and duration of established cardiovascular disease are associated with carotid media-intimal calcification. Old age is a strong predictor of carotid media intimal thickening. Female sex is associated with a valvular thickening.

CONCLUSIONS: Functional vitamin K deficiency is present in maintenance hemodialysis patients and serum osteocalcin is not associated with cardiovascular calcification.