Can osteoprotegerin be used to identify the presence and severity of coronary artery disease in different clinical settings?

PURPOSE: The biomarker Osteoprotegerin (OPG) is associated with coronary artery disease (CAD). The main purpose of this study was to evaluate the diagnostic value of OPG in healthy subjects and in patients with suspected angina pectoris (AP).

METHODS: A total of 1805 persons were enrolled: 1152 healthy subjects and 493 patients with suspected AP. For comparison 160 patients with acute myocardial infarction (MI) were included. To uncover subclinical coronary atherosclerosis, a non-contrast cardiac-CT scan was performed in healthy subjects; while in patients with suspected AP a contrast coronary angiography was used to detect significant stenosis. OPG concentrations were analyzed and compared between groups. ROC-analyses were performed to estimate OPG cut-off values.

RESULTS: OPG concentrations increased according to disease severity with the highest levels found in patients with acute MI. No significant difference (p = 0.97) in OPG concentrations was observed between subgroups of healthy subjects according to severity of coronary calcifications. A significant difference (p < 0.0001) in OPG concentrations was found between subgroups of patients with suspected stable AP according to severity of CAD. ROC-analysis showed an AUC of 0.62 (95% CI: 0.57-0.67). The optimal cut-off value of OPG (<2.29 ng/mL) had a sensitivity of 56.2% (95% CI: 49.2-63.0%) and a specificity of 62.9% (95% CI: 57.3-68.2%).

CONCLUSION: OPG cannot be used to differentiate between healthy subjects with low versus high levels of coronary calcifications. In patients with suspected AP a single OPG measurement is of limited use in the diagnosis of CAD.