The prognostic value of ORBIT risk score in predicting major bleeding in patients with acute coronary syndrome

Background: The most significant adverse effect of antithrombotic medication in acute coronary syndrome (ACS) is major bleeding, which is related to increased mortality. Studies on ORBIT risk score in predicting major bleeding in ACS patients are limited.

Objective: This research aimed to examine whether the ORBIT score calculated at the bedside can identify major bleeding risk in patients with ACS.

Methods: This research was retrospective, observational, and conducted at a single center. Analyses of receiver operating characteristics (ROC) were utilized to define the diagnostic value of CRUSADE and ORBIT scores. The predictive performances of the two scores were compared using DeLong's method. Discrimination and reclassification performances were evaluated by the integrated discrimination improvement (IDI), and net reclassification improvement (NRI).

Results: The study included 771 patients with ACS. The mean age was 68.7 ± 8.6 years, with 35.3 % females. 31 patients had major bleeding. Twenty-three of these patients were BARC 3 A, five were BARC 3 B, and three were BARC 3 C. Bleeding history [OR (95 % CI), 2.46 (1.02-5.94), p = 0.021], hemoglobin levels [OR (95 % CI), 0.54 (0.45-0.63), p < 0.001], and age > 74 years [OR (95 % CI), 1.03 (1.01-1.06), p = 0.039] were independent predictors of major bleeding. The ORBIT score was an independent predictor of major bleeding in the multivariate analysis: continuous variables [OR (95 % CI), 2.53 (2.61-3.95), p < 0.001] and risk categories [OR (95 % CI), 3.06 (1.69-5.52), p < 0.001]. Comparison of c-indexes for major bleeding events revealed a non-significant difference for the discriminative ability of the two tested scores (p = 0.07) with a continuous NRI of 6.6 % (p = 0.026) and an IDI of 4.2 % (p < 0.001).

Conclusion: In ACS patients, the ORBIT score independently predicted major bleeding.