HDCN Article Review/Hyperlink

Kohlmeier M, Saupe J, Shearer MJ, Schaefer K, Asmus G

Bone health of adult hemodialysis patients is related to vitamin K status

Kidney Int (Apr) 51:1218-1221 1997

The authors studied the incidence of fracture and prevalence of hyperparathyroidism in a group of hemodialysis patients as a function of serum phylloquinone concentrations. They reviewed records and X-rays for evidence of fractures in 68 patients prior to recruitment and followed them prospectively for 4 years. They found that 23 of the 68 had history of fracture at the time of enrollment and that 9 patients (5 of which had previously fractured) developed new fractures during the observation period. They found that the patients who fractured had significantly lower phylloquinone levels than those that did not fracture and that the degree of hyperparathyroidism was inversely correlated to the serum phylloquinone concentration.

This interesting observational study suggesting a relationship between vitamin K status and bone and mineral metabolism. It is not surprising that vitamin K plays a role in normal bone metabolism as vitamin K is required for the synthesis of osteocalcin and protein S in bone. However, this study does not demonstrate a direct correlation between vitamin K status and either bone disease or hyperparathyroidism. A single determination of phylloquinone can not be used to establish a relationship between vitamin K status and long term bone disease or the incidence of fractures. There was no data provided concerning the verification of presence or absence of fractures in all the patients reported. The study does not demonstrate a relationship between vitamin K and parathyroid hormone. The PTH assay used is a non- radioactive immunoassay and to my knowledge has not been adequately substantiated in patients with end stage renal disease. There was no information given regarding the calcium, phosphorus or vitamin D status of these patients, all of which are important modulators of PTH synthesis and secretion.

Comment: In summary, the authors put forth an interesting hypothesis, however more studies are required to determine what role vitamin K may play in the development of bone disease in dialysis patients. (Stuart Sprague, D.O., Northwestern University, Chicago, IL)