Validation of the Canada Acute Coronary Syndrome Risk Score for Hospital Mortality in the Gulf Registry of Acute Coronary Events‐2

Background Several risk scores have been developed for acute coronary syndrome (ACS) patients, but their use is limited by their complexity. The new Canada Acute Coronary Syndrome (C‐ACS) risk score is a simple risk‐assessment tool for ACS patients. This study assessed the performance of the C‐ACS risk score in predicting hospital mortality in a contemporary Middle Eastern ACS cohort. Hypothesis The C‐ACS score accurately predicts hospital mortality in ACS patients. Methods The baseline risk of 7929 patients from 6 Arab countries who were enrolled in the Gulf RACE‐2 registry was assessed using the C‐ACS risk score. The score ranged from 0 to 4, with 1 point assigned for the presence of each of the following variables: age ≥75 years, Killip class >1, systolic blood pressure 100 bpm. The discriminative ability and calibration of the score were assessed using C statistics and goodness‐of‐fit tests, respectively. Results The C‐ACS score demonstrated good predictive values for hospital mortality in all ACS patients with a C statistic of 0.77 (95% confidence interval [CI]: 0.74‐0.80) and in ST‐segment elevation myocardial infarction and non–ST‐segment elevation acute coronary syndrome patients (C statistic: 0.76, 95% CI: 0.73‐0.79; and C statistic: 0.80, 95% CI: 0.75‐0.84, respectively). The discriminative ability of the score was moderate regardless of age category, nationality, and diabetic status. Overall, calibration was optimal in all subgroups. Conclusions The new C‐ACS score performed well in predicting hospital mortality in a contemporary ACS population outside North America.