Validation of predictive factors for hospital admission in elderly patients transported by emergency medical services: a retrospective observational study

Background: As the global population ages, emergency department (ED) visits and hospital admissions among older adults are increasing, and many of these patients have complex medical and social backgrounds. A significant proportion of these visits may be avoidable, especially among those receiving home medical care. Avoidable hospitalizations can result in adverse outcomes such as functional decline and iatrogenic complications, and place additional burdens on healthcare systems. Identifying predictive factors for hospital admission in this population is essential to improve care quality, optimize resource use, and guide decision-making in prehospital settings. Methods: We conducted a retrospective observational study at Juntendo University Nerima Hospital in Japan. Patients aged 75 years or older who were receiving home medical care and who were transported to our hospital by emergency medical service (EMS) were included in this study. Clinical, demographic, and situational data were obtained from electronic medical records. The primary outcome was hospital admission. Univariate analyses were performed to identify potential predictors, followed by multivariate logistic regression to determine independent predictors. A statistical two-tailed significance level of 0.05 was used. Results: During the study period, 853 patients were transported to our hospital, and 738 met the inclusion criteria. Of these, 503 were admitted, and 235 were discharged from the ED. Factors significantly associated with admission in univariate analysis included lower Glasgow Coma Scale score; higher National Early Warning Score; oxygen therapy in the ED; and suspected diagnoses of infections, cerebrovascular disease, or cardiovascular disease. In multivariate analysis, independent predictors included suspected infection, cerebrovascular disease, cardiovascular disease, digestive disease, oxygen therapy in the ED, and decreased consciousness. Minor trauma and transient loss of consciousness were associated with lower odds of admission. Conclusions: In elderly home care patients transported by EMS, hospital admission was associated with suspected infection; cardiovascular, cerebrovascular, and digestive diseases; and oxygen therapy in the ED and decreased consciousness. These findings may assist in triage and decision-making in emergency care for this vulnerable population. Trial registration: This study was approved by the ethics committee at Juntendo University Nerima Hospital (approval number: E24-0452), and the study was carried out according to the principles of the Declaration of Helsinki. As this was a retrospective chart review, the requirement to obtain individual consent was waived by the Research Ethics Board.