Epperformed RUQ US:

1
Factors Associated with Utilization of Emergency
Medical Services in an Urban Academic Hospital
Jennifer Ruger, PhD Christopher Richter,
MD Lawrence Lewis, MD
Division of Emergency Medicine Washington
University School of Medicine St. Louis, Missouri
2
Presented at the American College of
Emergency Physicians (ACEP) Annual Meeting
3
Context

• Recent concern about ambulance diversion and
  emergency department (ED) overcrowding has
  increased scrutiny of the emergency medical
  services (EMS) system
• Little is known, however, about the factors
  associated with EMS use or the factors that favor
  the use of EMS transportation as compared to
  other modes of arrival

4
Background

• Previous studies have been limited in size,
  scope, and the ability to control for confounding
  factors, such as clinical acuity at presentation
• Moreover, they have primarily consisted of
  post-hoc investigations of EMS misuse or
  inappropriate use

5
Objective

• To identify factors associated with mode of
  transportation to an ED associated with an urban
  academic hospital

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Methods

• A retrospective, cross-sectional study of all
  patients seen during calendar year 2001 with
  complete data on mode of arrival in the ED of a
  large, urban academic hospital
• Data was obtained from three of the hospitals
  databases
• Clinical
• Admissions
• Financial

7
Methods
continued

• Mode of arrival was divided into six categories
• Bus
• Car
• Helicopter
• Walk-In
• City EMS
• County EMS

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Results
Calendar Year 2001 78,735 ED patients
Frequency
Percent
Car
53,784
70.5
City EMS
12,665
16.6
Bus
4,669
5.7
County EMS
3,855
5.1
Walk-in
1,394
1.8
Helicopter
253
0.3
9
Results
continued
Factors Significantly Associated with EMS Use

• Being in a motor vehicle crash
• OR 7.71 (95 CI 7.08 - 8.4)
• Suffering a gunshot or stab wound
• OR 5.95 (95 CI 4.68 - 7.55)
• Triage acuity level A or B
• OR 3.4 (95 CI 3.27 - 3.58)

.
.
.
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Results
continued
Factors Significantly Associated with EMS Use

• Being admitted to the intensive care unit or
  operating room or dying
• OR 2.71 (95 CI 2.39 - 3.08)
• Falling 0 to 10 feet
• OR 2.28 (95 CI 2.04 - 2.56)
• Having Medicaid Traditional
• OR 2.07 (95 CI 1.74 - 2.47)

.
.
.
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Results
continued
Factors Significantly Associated with EMS Use

• DRG severity level 4 (most severe)
• OR 1.98 (95 CI 1.68 - 2.34)
• Medicare Traditional
• OR 1.79 (95 CI 1.50-2.14)
• Being admitted to the hospital or dying after
  arriving at the ED
• OR 1.60 (95 CI 1.51-1.69)

.
.
.
12
Results
continued
Factors Significantly Associated with EMS Use

• Being a self-payor or uninsured
• OR 1.53 (95 CI 1.28 - 1.82)
• Being age 65 or older
• OR 1.48 (95 CI 1.36 - 1.62)
• DRG severity level 3
• OR 1.47 (95 CI 1.31 - 1.66)

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Discussion

• To our knowledge this study is the first to
  examine the relationship between a number of
  clinical and demographic variables and the chosen
  mode of transportation to an ED
• Our patient sample was large. Extensive
  clinical, financial and administrative data
  allowed us to examine and control for previously
  unstudied patient characteristics

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Conclusion

• In this study, EMS utilization related to
• Severity of injury or illness
• Age
• Health insurance status
• Patients utilizing EMS were more acutely sick or
  more severely injured than those not using EMS
• Our findings do not support the perception of
  significant inappropriate EMS utilization

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Recommendation

• Policy makers should proceed with caution in
  efforts to reduce ambulance utilization in order
  to address ED overcrowding and ambulance
  diversion