Abstract 17206: Osteopontin Levels in Patients at High Cardiovascular Risk

Introduction: Proteins which are involved in the bone metabolism have recently been discovered to have significant implications in the development of vascular disease and complications. Osteopontin (OPN) has been suggested as a biomarker of atherosclerosis and vascular calcification. Hypothesis: OPN levels may be used for risk stratification in patients with peripheral artery disease (PAD). Methods: 361 patients suffering from PAD were studied and followed-up for five years. 60 outcome events, defined as death, non-fatal myocardial infarction or non-fatal stroke, were observed. Multiplex bead array technology was used to measure serum levels of OPN at baseline. For basic analysis, the patients were divided into quartiles according to OPN levels. A Cox regression model was used to identify confounding variables. Results: A significantly different event-free survival could be observed between all groups (log-rank: p=0.049). When comparing the highest quartile to the rest of the cohort, a further increase in significance could be observed (log-rank: p=0.017). A cut-off point accommodating the most favorable sensitivity (50.0%) and specificity (66.4%) was determined for regression analysis. The hazard ratio was 2.13 (1.26-3.60) in the unadjusted model and reached 2.16 (1.21-3.84) after adjustment for age, gender, diabetes, low-density lipoprotein cholesterol, blood pressure, smoking, c-reactive protein and renal function. Conclusions: Our results suggest an association between OPN levels and the rate of cardiovascular events in high risk patients. In our observations this relation was independent of established risk factors.