Osteoprotegerin and bone mineral density in hemodialysis patients

Osteoprotegerin is a soluble glycoprotein that belongs to the tumor-necrosis-factor receptor superfamily. In vitro, osteoprotegerin blocks osteoclastogenesis in a dose-dependent manner. The serum osteoprotegerin level shows a positive correlation with bone metabolism markers and a negative correlation with bone mineral density in healthy persons, but these relationships are unclear in hemodialysis patients. We investigated the role of osteoprotegerin in bone loss in hemodialysis patients.

We measured baseline serum osteoprotegerin, bone metabolism markers, and bone mineral density in hemodialysis patients. A total of 201 patients (114 men and 87 women) were followed for 12 months, and bone mineral density was measured again to calculate the annual percent change in bone mineral density. Serum osteoprotegerin was also measured in 20 healthy persons.

The osteoprotegerin levels of the hemodialysis patients were about three times higher than those of the healthy controls. The osteoprotegerin level showed a negative correlation with various bone metabolism markers. In multiple regression analysis, the annual percent change in bone mineral density showed a positive correlation with osteoprotegerin level, while there was a negative correlation with duration of hemodialysis and intact parathyroid hormone level. The osteoprotegerin levels of the hemodialysis patients were about three times higher than those of the healthy controls. The osteoprotegerin level showed a negative correlation with various bone metabolism markers. In multiple regression analysis, the annual percent change in bone mineral density showed a positive correlation with osteoprotegerin level, while there was a negative correlation with duration of hemodialysis and intact parathyroid hormone level.

These correlations of osteoprotegerin are opposite to those found in healthy persons. However, osteoprotegerin might act to prevent bone loss even in hemodialysis patients.