Evaluation of the Orbit Bleeding Risk Score as Predictor of Major Bleeding in Patients with Acute Coronary Syndrome

Abstract

Background: Major bleeding is the most important complication of antithrombotic treatment in acute coronary syndrome (ACS) and is associated with higher mortality. Assessing the risk of bleeding is a challenge. The usefulness of the Orbit Bleeding Score (ORBIT) to assess the risk of bleeding in ACS has been scarcely studied. Objective: The aim of this study was to evaluate the ORBIT score as a predictor of major bleeding in patients hospitalized for ACS in whom anticoagulation is decided as part of the antithrombotic strategy. Methods: Patients admitted to two coronary care units with diagnosis of ACS who received anticoagulation as part of the antithrombotic therapy were retrospectively included in the study. The CRUSADE, ACTION-GWTG and ORBIT scores were calculated using the admission clinical data. The primary endpoint was major bleeding, defined as BARC 3 or 5 classification. Results:The study included 762 patients. Major bleeding occurred in 3.4% of cases. In the univariate analysis, the three scores were predictors of major bleeding, while in the multivariate analysis only the ORBIT score was an independent predictor of major bleeding (OR: 2.46, 95% CI 1.61-3.97, p <0.001). The area under the ROC curve was 0.70, 0.68 and 0.80 for the ACTION-GWTG, CRUSADE and ORBIT scores, respectively. The ORBIT score presented a higher area under the curve than the CRUSADE score (p=0.03) but without significant difference with the ACTION-GWTG score (p=0.06) Conclusions: The ORBIT score was the only independent predictor of major bleeding, presenting a better discrimination capacity than the CRUSADE score and a tendency to better capacity than the ACTION-GWTG score.