EMS/ORIGINAL CONTRIBUTION Patient-Specific Predictors of Ambulance Use From the Division of Emergency Medicine, Department of Medicine, Beth Israel Deaconess Medical Center*; Harvard University School of Public Health¢; the Division of General Medicine, Department of Medicine, Brigham and Women's HospitaP; and Partners HealthCare System", Boston, Massachusetts. Receivedfor publicationApril 22, 1996. Revision received October31, 1996. Acceptedfor publication November i2, 1996. Abstract presented at the 5ociety for Academic EmergencyMedicineAnnual Meeting, San Antonio, May 1995. Partially sponsored by the Risk Management Foundation, Cambridge, Massachusetts. Copyright © by the American College of Emergency Physicians. Donald W Rucker, MD, MBA* Roger A Edwards, ScB*" Helen R Borstin, MD, MPH §* Anne C O'Neil, MPH* Troyen A Brennan, MD, JD, MPH*§ Study objective: To determine patient-specific socioeconomic and health status characteristics for patients arriving by ambulance at an emergency department. Methods: Ambulance use among adult ED patients presenting with abdominal pain, chest pain, head trauma, or shortness of breath was studied at five urban teaching hospitals in the north- eastern United States. Cross-sectional analysis within a prospec- tive cohort study of 4,979 consecutive patients was performed using an interval sequence subset of 2,315 patients (84% of those eligible) to whom questionnaires were administered. Ambulance use (21% of surveyed patients; 26% of all patients) was analyzed with logistic regression. Results: Predictors of ambulance use included age greater than 65 years (odds ratio [OR], 1.95; 95% confidence interval lOll, 1.34 to 2.82); clinical severity (OR,3.11; 95% CI, 2.27 to 4.25); poverty (OR, 1.40; 95% CI, 1.08 to 1.83); physical function (OR, 1.05; 95% CI, 1.02 to 1.09 for each point of worsening function on a 12-point physical function scale); and various types of health insurance coverage. Race, sex, education, Medicaid coverage, frequency of E0 use, living arrangements, and primary physician availability were not predictive in multivariate analysis of surveyed patients. Conclusion: Ambulance use varies by age, clinical severity, income, patient-specific characteristics of physical function, and type of health insurance. Medicaid coverage and frequent ED use are not predictive of increased ambulance use. [Rucker DW, Edwards RA, Burstin HR, O'Neil AC, Brennan TA: Patient-specific predictors of ambulance use. Ann Emerg Med April 1997;29:484-491.] 4 8 4 ANNALS OF EMERGENCY MEDICINE 29:4 APRIL 1997