Inpatient admissions from the ED for adults with injuries: the role of clinical and nonclinical factors.

INTRODUCTION: Inpatient hospital costs represent nearly a third of heath care spending. The proportion of inpatients visits that originate in the emergency department (ED) has been growing, approaching half of all inpatient admissions. Injury is the most common reason for adult ED visits, representing nearly one-quarter of all ED visits.

OBJECTIVE: The objective was to explore the association of clinical and nonclinical factors with the decision to admit ED patients with injury.

RESEARCH DESIGN AND PARTICIPANTS: This is a retrospective cohort study of injury-related ED encounters by adults in select states in 2009. We limited the study to ED visits of persons with moderately severe injuries. We used logistic regression to calculate the marginal effects, estimating 4 equations to account for different risk patterns for older and younger adults, and types of injuries. Regression models controlled for comorbidities, injury characteristics, demographic characteristics, and state fixed effects.

RESULTS: Injury location, type, and mechanism and comorbidities had large effects on hospitalization rates as expected. We found higher inpatient admission rates by level of trauma center designation and hospital size, but findings differed by age and type of injury. For younger adults, patients with private insurance and patients who traveled more than 30 miles were more likely to be admitted.

CONCLUSIONS: There is great variation in inpatient admission decisions for moderately injured patients in the ED. Decisions appear to be dominated by clinical factors such as injury characteristics and comorbidities; however, nonclinical factors, such as type of insurance, hospital size, and trauma center designation, also play an important role.