Home Medical Care and Reduced Risk of Rehospitalization After Aspiration Pneumonia in an Elderly Japanese Population: A Nationwide Inpatient Database Study

Introduction Aspiration pneumonia in elderly patients is a major public health burden associated with high mortality and frequent rehospitalization. In response to a rapidly aging society, Japan's healthcare system is promoting a shift from hospital-centric treatment to home medical care. Although the benefits of home medical care have been established in settings such as palliative care, its effectiveness in preventing readmission of elderly patients recovering from aspiration pneumonia remains unclear. This study evaluated whether initiation of home medical care at discharge is associated with a lower risk of 365-day rehospitalization among elderly patients admitted for aspiration pneumonia. Methods This retrospective cohort study was conducted using data from Japan's nationwide Diagnosis Procedure Combination database from April 1, 2015, to March 31, 2022. We identified patients aged ≥65 years who were hospitalized for their first episode of aspiration pneumonia (International Classification of Diseases, Tenth Revision (ICD-10) code: J69.0). We then excluded patients who were already receiving home medical care, experienced in-hospital death, or were discharged to other hospitals or nursing facilities. We conducted 1:4 propensity score matching with adjustment for age, sex, activities of daily living, and comorbidities to compare patients who received home medical care at discharge (home medical care group) and those who did not (control group). The primary outcome was all-cause rehospitalization to the same hospital within 365 days, analyzed using a Cox proportional hazards model. The secondary outcomes included rehospitalization for specific causes. Results Among 183,770 eligible patients, 12,454 in the home medical care group were matched to 49,816 in the control group. The baseline characteristics were well balanced after matching (standardized mean differences, <0.10 for all). The 365-day all-cause rehospitalization rate was lower in the home medical care group than in the control group (5,317 (42.7%) vs. 22,858 (45.9%); p < 0.001). Home medical care was associated with a lower risk of all-cause rehospitalization (hazard ratio (HR), 0.91; 95% confidence interval (CI), 0.89-0.94; p < 0.001). Regarding secondary outcomes, the home medical care group had lower risks of rehospitalization for aspiration pneumonia (HR, 0.92; 95% CI, 0.88-0.96; p < 0.001), urinary tract infections (HR, 0.84; 95% CI, 0.73-0.96; p = 0.009), and fractures (HR, 0.69; 95% CI, 0.56-0.85; p < 0.001). Conclusions The initiation of home medical care at discharge for elderly patients recovering from aspiration pneumonia was associated with a lower risk of 365-day all-cause rehospitalization. The risk reduction was particularly notable for readmission for aspiration pneumonia, urinary tract infections, and fractures. These findings support the potential value of home medical care, which has been expanded to manage an aging population and reduce the burden on acute-care hospitals.