Osteocalcin Testing in Type 2 Diabetes: Comparison of Two Fully Automated Immunoassays and Relevance for Risk Stratification.

Background: Accumulating evidence suggests interactions between bone and energy metabolism in patients with type 2 diabetes (T2DM). Recently, the role of osteocalcin (OC), an osteoblast-specific protein, was suggested as a regulator of glucose metabolism and fat mass. Methods: We determined the circulating levels of OC with two different assays in T2DM patients. The relationship of OC with established biomarkers of bone and mineral metabolism as well as biomarkers related to cardiovascular risk was also investigated. Results: OC levels measured with both methods were significantly lower in T2DM patients in comparison to healthy individuals but assays were not commutable. In multiple regression analysis OC levels were negatively correlated to HbAlc and positively correlated to PTH 1-84 and Beta-crosslaps. OC levels were significantly correlated to NT-proBNP but not to hsTnT. Conclusions: Measurement of OC in T2DM might assist physicians for risk stratification of T2DM patients.