Osteocalcin as a predictor of bone fracture in children with chronic kidney diseases

The associations between biochemical indicators of osteocalcin and bone health are fairly well established in adults through observational studies. In this context, our objective was to assess serum level of uncarboxylated osteocalcin (uOC) and its relation to the incidence of bone fractures other bone health indices in children with CKD.

We enrolled 102 patients classified into two groups: group A: CKD without KRT; group B: CKD on regular HD. The patients were followed throughout the study period. The study's endpoint was either the occurrence of a bone fracture or the conclusion of the study period. Another 22 healthy individuals were involved as a control group. We measured uOC and various indicators of bone health including bone-specific alkaline phosphatase (BAP) on the same day of the fracture or at the end of the study period.

uOC was found significantly higher in CKD children in comparison to the control group (p <0.001). Moreover, its level was significantly higher in the HD group compared to CKD without KRT group (p = 0.047). In patients with fractures, uOC and BAP were significantly higher compared with patients without fractures (p < 0.001 and 0.019, respectively). By logistic regression analysis, uOC was the only predictor of bone fractures (p = 0.027, OR = 1.011).

Elevated uOC levels were observed in children with CKD who experienced fractures, and these levels showed a correlation with BAP. Furthermore, uOC appears to be a reliable indicator of bone fractures in this population.