Supplementary Material for: Developing and validating a simple risk score for patients with acute myocardial infarction

Introduction: Mortality from acute myocardial infarction (AMI) remains substantial. The current study is aimed at developing a novel simple risk score for AMI. Methods: The Coronary Artery Tree description and Lesion EvaluaTion (CatLet) extended validation trial (ChiCTR2000033730) and the CatLet validation trial (ChiCTR-POC-17013536), both being registered with chictr.org, served as the derivation and validation datasets, respectively. Both datasets included 1018 and 308 patients, respectively. They all suffered from AMI and underwent percutaneous intervention (PCI). The endpoint was 4-year all-cause death. Lasso regression analysis was used for covariate selection and coefficient estimation. Results: Of 26 candidate predictor variables, four strongest predictors for 4-year mortality were included in this novel risk score with an acronym of BACEF (serum alBumin, Age, serum Creatinine, and LVEF). This score was well calibrated and yielded an AUC (95%CI) statistics of 0.84(0.80-0.87) in internal validation, 0.89(0.83-0.95) in internal-external (temporal) validation, and 0.83(0.77-0.89) in external validation. Notably, it outperformed the ACEF, ACEFII, GRACE scores with respect to 4-year mortality prediction. Conclusion: A simple risk score for 4-year mortality risk stratification was developed, extensively validated, and calibrated in patients with AMI. This novel BACEF score may be a useful risk stratification tool for patients with AMI.