Impact of Elderly Acute Care Discharge Services on Prevention of Rehospitalisation: A Retrospective Cohort Study Using National Health Data from Kita Ward, Tokyo

Introduction: Integrated care poses a significant challenge for healthcare policies in Japan as evaluation of hospital discharge services is limited. This study aimed to elucidate the effects of discharge services for elderly acute-care patients on preventing rehospitalisation. Methods: A retrospective cohort study was conducted using national health data from Kita Ward, Tokyo. Survival analysis was performed with a Cox proportional hazards model, with readmission hazard ratios (HRs) as the primary endpoint. Subgroup analysis examined interactions between each discharge service category (dummy variable) and readmission. Results: The study encompassed 6,681 subjects. The Cox model adjusted for age, gender, and complications revealed increased readmission events in the discharge service group (HR = 2.92, 95% CI 2.60-3.27). Subgroup analysis by age and length of hospital stay identified a preventive effect in the 85-year-old group (HR = 0.68, 95% CI 0.49-0.93) and 15-21-day length of stay group (HR = 0.73, 95% CI 0.53-1.01), suggesting that discharge services may inadvertently lower barriers to readmission due to healthcare system influences. Conclusion: While discharge services may elevate readmission demand, they appear to have a preventive effect for individuals aged 85 and over or with an average length of stay of 15-21 days.