Influence of comorbidities, geriatric syndromes, and frailty on mortality risk by discharge destination in older adults after acute hospitalization: a nationwide cohort study

Background: This study investigated its impact of discharge destination on mortality risk among older adults following acute hospital discharge, focusing on the effects of frailty, geriatric syndromes, and comorbidities. Methods: Nationwide claims data from the South Korean National Health Insurance Service of individuals aged ≥65 years who were discharged from acute care hospitals in 2017 were retrospectively analyzed, with participants followed for mortality outcomes over 4 years. Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios (aHR) for mortality according to discharge destination and geriatric status. Results: This study included 1,115,556 participants (mean age, 75.5 years; 45.6% men). The most common discharge destination was home (76.5%), followed by tertiary/general hospitals (15.2%), long-term care hospitals (5.2%), hospitals (2.3%), and other facilities (0.8%). Patients discharged to long-term care hospitals were older, had a higher comorbidity burden, and more frequently had disabilities or geriatric syndromes than their counterparts. Mortality risk was significantly higher among those discharged to tertiary/general hospitals (aHR 1.806, 95% CI: 1.793–1.820), general hospitals (aHR 1.480, 95% CI: 1.453–1.507), and long-term care hospitals (aHR 2.922, 95% CI: 2.892–2.952) than among those discharged to home. Higher Charlson comorbidity index (≥3), more geriatric syndromes, and severe frailty were all independently associated with increased mortality risk. Conclusion: Discharge destination, frailty, geriatric syndromes, and comorbidities independently and interactively influenced the mortality risk in older adults after acute hospitalization. Tailored post-discharge management strategies are necessary, particularly for patients with frailty and multimorbidity in community settings.