Ambulance use and subsequent fragmented hospital readmission among older adults

Interhospital care fragmentation, when a patient is readmitted to a different hospital than they were originally discharged from, occurs in 20%-25% of readmissions. Mode of transport to the hospital, specifically ambulance use, may be a risk factor for fragmented readmissions. Our study seeks to further understand the relationship between ambulance transport and fragmented readmissions in older adults, a population that is at increased risk for poor outcomes following fragmented readmissions.

We analyzed inpatient claims from Medicare beneficiaries in 2018 who had a hospital admission for select Hospital Readmission Reduction Program Conditions (acute myocardial infarction, congestive heart failure, chronic obstructive pulmonary disease, pneumonia) as well as dehydration, syncope, urinary tract infection, or behavioral issues. We evaluated the associations between ambulance transport and a fragmented readmission using logistic regression models adjusted for demographic, clinical, and hospital characteristics.

The study included 1,186,600 30-day readmissions. Of these, 46.8% (n = 555,847) required ambulance transport. In fully adjusted models, taking an ambulance to the readmission hospital increased the odds of a fragmented readmission by 38% (95% CI 1.32, 1.44). When this association was examined by readmission major diagnostic category (MDC), the strongest associations were seen for Factors Influencing Health Status and Other Contacts with Health Services (i.e., rehabilitation, aftercare) (AOR 3.66, 95% CI 3.11, 4.32), Mental Diseases and Disorders (AOR 2.69, 95% CI 2.44, 2.97), and Multiple Significant Trauma (AOR 2.61, 95% CI 1.56, 4.35). When the model was stratified by patient origin, ambulance use remained associated with fragmented readmissions across all locations.

Ambulance use is associated with increased odds of a fragmented readmission, though the strength of the association varies by readmission diagnosis and origin. Patient-, hospital-, and system-level interventions should be developed, implemented, and evaluated to address this modifiable risk factor.