The 130th Annual Meeting of APHA

Abstract #45264

Robert James Rydman, PhD, Department of Emergency Medicine, Cook County Hospital/Rush University, 1900 W. Polk St. 10th floor, Chicago, IL 60612, 312-996-8010, rjrydman@uic.edu, Pamela Diaz, MD, Chicago Department of Health - CDC, Ogden and Taylor, Chicago, IL 60612, Rebecca Roberts, MD, Department of Emergency Medicine, Cook County Hospital, 1900 West Polk, 10th Floor, Chicago, IL 60612, and Brandon Zagorski, MPH, Dept Emerg Med, Cook County Hospital, 1900 W. Taylor Street, 10th Floor, Chicago, IL 60612.

Background: Hospital Emergency Departments (ED) have over 100 million patient visits per year making them an ideal place for surveillance of events resulting from possible bioterrorism. As part of a CDC-funded B2 Bioterrorism project, an urban ED with an annual census of 120,000 visits studied the numbers of unduplicated patients, and the rate and risk of patients returning to the ED following an initial index visit over a 4.5 person year cycle of events. Methods: Cross sectional analysis of ED database consisting of 4.5 years, 1/1/97-7/1/01, 596,306 visits. Unduplicated case enumeration consisted of eliminating same day return visits due to possible enrollment errors. Frequency distributions of repeat visits were made by number of non same day visits per patient. Actuarial analysis of life tables for repeat visits were at 50 day intervals with survival rates and hazard scores. Results: 596,306 visits were analysed resulting in 564,361 valid visits. Number of unduplicated patients was 281,358 (49.8%). 177,140 (63%) patients visited the ED once. 104,218 had greater than one visit (37%), with 51,446 having 2 visits (49%) and 52,772 having three or more visits (51%). Survival rate at 100 days was 60%, 42% at 200 days, and 31% at 300 days. Conclusion: Out of the 100 million ED visits made per year, unselected by age, race, occupation or ability to pay, no one has quantified the unduplicated patient number this reflects. Unduplicated patient counts are necessary for epidemiologic analyses by person, time, or place. This is a prerequisite for Bioterrorism surveillance.

Learning Objectives:

• Attendees will learn 5 essential analytic areas of emphasis necessary to ED Bioterrorism Surveillance.
• Attendees will learn the importance of unduplicated counts of patients as opposed to patient visit volume for person, time, and place epidemiologic analysis.
• Attendees will gain an appreciation of the ED as a public health surveillance site.

Keywords: Bioterrorism, Emergency Department/Room

Related Web page: www.ccbh.org

Presenting author's disclosure statement:
Organization/institution whose products or services will be discussed: Cook County Hospital, Department of Emergency Medicine; and Chicago Department of Health, Infectious Disease Section
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.