Risk evaluation of new-onset atrial fibrillation complicating ST-segment elevation myocardial infarction: A comparison between GRACE and CHA₂DS₂-VASc scores

Purpose: New-onset atrial fibrillation (NOAF) is a common finding in patients with myocardial infarction (MI), but few studies are available regarding the prediction model for its risk estimation. Although Global Registry of Acute Coronary Events (GRACE) risk score (RS) has been recognized as an effective tool for the risk evaluation of clinical outcomes in patients with MI, its usefulness in the prediction of post-MI NOAF remains unclear. In this study, we sought to validate the discrimination performance of GRACE RS in the prediction of post-MI NOAF and to make a comparison with that of the CHA₂DS₂-VASc score in patients with ST-segment elevation myocardial infarction (STEMI). Patients and methods: A total of 488 patients with STEMI who were admitted to our hospital between May 2015 and October 2016 without a history of atrial fibrillation were retrospectively evaluated in this study. GRACE and CHA₂DS₂-VASc scores were calculated for each patient. Patients were divided into low (GRACE RS≤125)-, intermediate (GRACE RS 126–154)-, and high (GRACE RS≥155)-risk groups. Receiver operating characteristic curve analyses were performed to evaluate the discrimination performance of both RSs. Model calibration was evaluated by using Hosmer–Lemeshow goodness-of-fit test (HLS). Results: Of the 488 eligible patients, 49 (10.0%) developed NOAF during hospitalization. In the overall cohort, the discrimination performance of GRACE RS (C-statistic: 0.76, 95% CI: 0.72–0.80) was significantly better than that of CHA₂DS₂-VASc score (C-statistic: 0.68, 95% CI: 0.64–0.72; comparison p=0.03). For subgroup analysis, GRACE RS tended to be better than the CHA₂DS₂-VASc score in all but the intermediate-risk group as evidenced by C-statistics of 0.60 and 0.65 for GRACE and CHA₂DS₂-VASc scores, respectively. Excellent calibration was achieved except for GRACE RS in females (HLS p=0.05). Conclusion: The diagnostic performance of GRACE RS is relatively high as well as better than that of the CHA₂DS₂-VASc score with respect to the prediction of post-MI NOAF.