Tehran University of Medical Sciences Frontiers in Emergency Medicine 2717-3593 6 4 2022 05 15 e49 e49 Ahmad Abbasian Prehospital and Hospital Emergency Research Center, Tehran University of Medical Sciences, Tehran, Iran Leyla Farshidpour UC Davis School of Medicine, Davis, California, USA Mehdi Chegin Emergency Medicine Department, Imam Khomaini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Talayeh Mirkarimi Emergency Medicine Department, Qazvin University of Medical Sciences, Qazvin, Iran Amin Doosti-Irani Department of Epidemiology, School of Public Health and Modeling of Noncommunicable Diseases Research Center, Hamadan University of Medical Sciences, Hamadan, Iran Hadi Mirfazaelian Emergency Medicine Department, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran 2022 05 15 2022 05 15 Objective: About one out of every 10 patients with chest pain in the emergency department (ED) are finally diagnosed with acute coronary syndrome (ACS). A HEART score of ≤ 3 has been shown to rule out ACS with a low risk of major adverse cardiac events (MACE) occurrence. It has been proposed that a negative CARE rule (≤1), which stands for the first four elements of the HEART score and excludes the troponin assay requirement, may have similar rule-out reliability. This study aimed to externally validate the CARE rule. Methods: In this multicenter, observational study a convenience sample consisting of patients over the age of 15 who had at least one troponin study were included. The performance of the CARE rule at the cut-off ≤1 for MACE prediction was assessed and compared to a HEART score of ≤3 and physicians’ gestalt. MACE was defined as myocardial infarction, coronary angioplasty, coronary artery bypass graft, and all-cause mortality in 6 weeks. Results: The data of 154 patients was analyzed. Of these, 121 patients had a negative CARE score of ≤1 and 33 individuals had a positive CARE score. Of those with a negative CARE score, only 1 (3%) experienced an adverse cardiac event while in those with a positive CARE score, 26 individuals (16.88 %) experienced MACE. The sensitivity of the CARE rule was 96.15% and the specificity was 25% with a negative likelihood ratio (LR-) of 0.15. The indices for HEART score were 88%, 59.69%, and 0.2, respectively. In comparison, physicians' gestalt had a sensitivity of 96%, specificity of 49.22%, and a LR- of 0.08. Of note, utilizing the CARE rule with a cut-off of <3 showed sensitivity of 96%, specificity of 41.86%, and a LR- of 0.1. Conclusion: The CARE rule miss rate in MACE was more than 2% and while its performance was better than the HEART score, physicians’ gestalt outperformed both rules for ruling out MACE. https://fem.tums.ac.ir/index.php/fem/article/view/1014 https://fem.tums.ac.ir/index.php/fem/article/download/1014/418