Multimorbidity frailty index and clinical outcomes among 42,989 older heart failure patients directly discharged from emergency departments: A nationwide retrospective cohort study

Aims: Frailty, a common and clinically significant condition in older adults with heart failure (HF), is often overlooked in emergency department (ED) settings. This study aims to evaluate the impact of frailty on clinical outcomes in older adults directly discharged from the ED due to HF. Methods and results: This retrospective cohort study used data from Taiwan's National Health Insurance (NHI) database, identifying older adults (≥65 years) discharged from the ED due to HF between 2017 and 2021. Frailty was assessed using a 38-item multimorbidity frailty index (mFI) derived from ICD-10-CM codes, stratifying patients into fit, mild-to-moderately frail, and severely frail. Outcomes included all-cause mortality, all-cause readmissions, and HF-related readmissions. Cox regression and Fine and Gray models estimated the impact of frailty on these outcomes. Among 42,989 older HF patients (mean age 80.7 ± 8.2 years, 55.5 % female), 57.8 % were frail (46.4 % mild-to-moderately frail and 11.4 % severely frail). Six-month mortality rates were 12.0 % in fit, 16.0 % in mild-to-moderately frail, and 19.4 % in severely frail patients. Readmission rates showed similar patterns. The severely frail group had higher risks of mortality (aHR 1.44, 95 % CI 1.33–1.55), all-cause readmissions (sHR 1.69, 95 % CI 1.62–1.76), and HF-related readmissions (sHR 1.59, 95 % CI 1.48–1.71). Conclusion: Frailty is prevalent among older adults directly discharged from the ED due to HF and significantly elevates risks of mortality and readmissions. These findings highlight the need for frailty assessment in ED settings for older HF patients to optimize care planning, and improve outcomes.