Yamada S, et al. - Researchers sought to develop frailty-based predictive criteria in heart failure (HF) patients (FLAGSHIP)-aimed at developing frailty criteria based on HF-specific outcomes, proposing a theory of the possible mechanisms of the manifestations of frailty in HF, and examining how outpatient cardiac rehabilitation impacts frailty via a nationwide cohort study. They enrolled ambulatory patients admitted with acute HF or exacerbation of HF and elderly patients (age ≥ 70 years) admitted for acute myocardial infarction. Cardiac events including cardiac mortality and HF-related readmission after discharge are included as the primary endpoints, while readmissions because of fracture or pneumonia and all-cause mortality are included as secondary endpoints. It is expected that for the stratification of patients at risk to functional decline after medical or surgical treatment, diagnostic criteria on frailty developed by FLAGSHIP may become a novel indicator, and in turn may contribute to the best practices in the long-term management of HF.