Preoperative frailty for predicting in-hospital mortality in patients after cardiac surgery: an interpretable Machine learning model based on a retrospective multicenter cohort study. - Ya-nan Ge; Yu-man Ouyang; Qian-qian Li; Jie Huang; Dai Li; Chang-li Wang; Ya-lin Zhu; Jia-feng Wang (Int. J. Medical Informatics, 2026)