User Support

May 2013

Andrés Villaveces, M.D., M.P.H., Ph.D., Ryan Mutter, Ph.D., Pamela L. Owens, Ph.D., and Marguerite L. Barrett, M.S.



Introduction

One person dies from an injury every 3 minutes in the United States.¹ More Americans aged 1-44 years die from injuries such as motor vehicle crashes, falls, or homicides than from any other cause, including cancer, HIV, or influenza.² Non-fatal injuries can have physical and financial consequences that impact the lives of individuals and their families. In addition, the treatment of injuries places an enormous burden on hospital emergency departments (EDs) and trauma care systems.³

This Statistical Brief presents data from the Healthcare Cost and Utilization Project (HCUP) Nationwide Emergency Department Sample (NEDS) on the most common causes of injuries that were treated in the ED in 2010. These visits began with treatment in the ED and either resulted in admission to the same hospital or did not result in admission (i.e., the patient was treated, stabilized and released from the ED; transferred to another hospital; or died in the ED). ED visits for injury are described based on the external cause of injury (e.g., falls, transport related, poisoning, burns, drowning, other blunt injuries). The distribution of injuries by severity, percentage of ED visits that result in admission to the same hospital, and total costs for admitted patients are also presented.

Findings

Injuries treated in the emergency department
Of the 129 million ED visits in the United States in 2010, over 22 million (17 percent) were due to injuries. Patients younger than 30 years accounted for 48 percent of all injury-related ED visits, with pediatric patients (younger than 18 years) accounting for over one-quarter of all injury-related ED visits (figure 1).

Table 1 presents the distribution of ED visits by cause of injury overall and by age group. The most common cause was falls (35.7 percent), followed by being struck by an object (18.3 percent) and motor vehicle injuries (12.5 percent). Although falls were the most common type of injury that resulted in an ED visit for all age groups, falls were much more common among those aged 65 years and older (71.2 percent) compared to the younger age groups (ages 0—17, 37.3 percent; ages 18—44, 21.9 percent; ages 45—64, 36.7 percent). Children (ages 0—17) had the largest proportion of injuries related to being struck by an object (26.5 percent) compared to the older age groups (ages 18—44, 19.7 percent; ages 45—64, 12.7 percent; ages 65 and older, 6.2 percent).

Primary payer and severity of injuries treated in the emergency department
Figure 2 presents the distribution of injury-related ED visits by expected primary payer. Injury-related ED visits were covered most frequently by private insurance (38 percent) or Medicaid (20 percent). Uninsured patients represented 18 percent of all injury-related ED visits.

Figure 3 presents the distribution of injury-related ED visits by severity. Eighty-nine percent of the injuries were classified as mild. Almost all mild injuries (96 percent) were treated and released from the ED (data not shown). Severe to profound injuries accounted for only one percent of the injuries.

Cost of injuries when patient is admitted to the hospital for treatment
Table 2 reports that 6.5 percent of injury-related ED visits resulted in an admission to the hospital. Injuries that most frequently led to admissions were related to firearms (admission rate of 37.9 percent) and poisoning (admission rate of 35.7 percent). One in five injuries due to suffocation (admission rate of 22.8 percent) or drowning (admission rate of 20.3 percent) was admitted. The admission rate for all other types of injuries was less than 10 percent.

ED and inpatient costs across all causes of injury in 2010 were $19.4 billion for admitted patients. The cause of injury with the highest associated cost was falls ($9.2 billion), followed by motor vehicle transport injuries ($5.1 billion) and poison-related injuries ($1.8 billion).

Data Source

The estimates in this Statistical Brief are based upon data from the Healthcare Cost and Utilization Project (HCUP) 2010 Nationwide Emergency Department Sample (NEDS).

Definitions

Injury
Emergency department (ED) visits with injuries are identified by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes. ICD-9-CM assigns numeric codes to diagnoses. There are approximately 14,000 ICD-9-CM diagnosis codes.

Injuries are identified by the first-listed diagnosis using a scheme recommended by the Safe States Alliance.⁴ The table below lists the diagnosis codes in the range 800—999 used to identify injuries:

Causes of injury
The cause of injury is determined by the external cause of injury codes (a subset of the ICD-9-CM diagnosis codes). The codes are consistent with the classification system used by the Centers for Disease Control (CDC) that is documented at http://www.cdc.gov/injury/wisqars/ecode_matrix.html. The NEDS includes 11 data elements that identify the cause of the injury: cutting, drowning, falling, fire, firearm, machinery, motor vehicle, natural/environmental, poisoning, suffocation, and being struck. This Statistical Brief allows a single ED visit to include multiple causes if there were multiple injuries. For example, if an individual was treated in the ED following a motor vehicle accident in which he/she was burned by an engine fire, the ED visit would be counted under motor vehicle injuries and fire injuries.

Injury severity
The injury severity score is assigned using a publicly available Stata program for Injury Classification (ICDPIC). The program uses ICD-9-CM diagnosis codes to assign a severity score ranging from 1 to 75, with 75 being the most severe. The Injury Severity Score (ISS) is based on an anatomical scoring system that provides an overall score for patients with multiple injuries. Each injury is assigned an Abbreviated Injury Scale (AIS) score, allocated to one of six body regions: head, face, chest, abdomen, extremities (including pelvis), and external. Only the highest AIS score in each body region is used. To produce the ISS score, the score of the three most severely injured body regions is squared and the results are added to produce the ISS score. The ISS correlates linearly with mortality, morbidity, hospital stay, and other measures of severity. Injuries are categorized by severity score as mild (less than 9), moderate (9-15), severe (16-25), and profound (greater than 25). More information on the ISS is available at https://aci.health.nsw.gov.au/get-involved/institute-of-trauma-and-injury-management/data/injury-scoring/injury_severity_score.

Types of hospitals included in HCUP
HCUP is based on data from community hospitals, which are defined as short-term, non-Federal, general, and other hospitals, excluding hospital units of other institutions (e.g., prisons). HCUP data include obstetrics and gynecology, otolaryngology, orthopedic, cancer, pediatric, public, and academic medical hospitals. Excluded are long-term care, rehabilitation, psychiatric, and alcoholism and chemical dependency hospitals. Community hospitals included in the Nationwide Emergency Department Sample (NEDS) have hospital-based emergency departments with no more than 90 percent of their ED visits resulting in admission.

Unit of analysis
The unit of analysis is the emergency department (ED) encounter, not a person or patient. This means that a person who is seen in the ED multiple times in one year will be counted each time as a separate "encounter" in the ED.

Costs and charges
Total hospital charges were converted to costs using HCUP Cost-to-Charge Ratios based on hospital accounting reports from the Centers for Medicare & Medicaid Services (CMS).⁵ Costs will reflect the actual expenses incurred in the production of hospital services, such as wages, supplies, and utility costs; charges represent the amount a hospital billed for the case. Total costs include costs for both ED and inpatient services and are only reported for ED visits that result in admission. For each hospital, a hospital-wide cost-to-charge ratio is used. Hospital charges reflect the amount the hospital billed for the entire hospital stay and do not include professional (physician) fees. For the purposes of this Statistical Brief, costs are reported in millions.

Payer
Payer is the expected primary payer for the hospital stay. To make coding uniform across all HCUP data sources, payer combines detailed categories into general groups:

• Medicare: includes patients covered by fee-for-service and managed care Medicare
• Medicaid: includes patients covered by fee-for-service and managed care Medicaid
• Private Insurance: includes Blue Cross, commercial carriers, and private health maintenance organizations (HMOs) and preferred provider organizations (PPOs)
• Other: includes Worker's Compensation, TRICARE/CHAMPUS, CHAMPVA, Title V, and other government programs
• Uninsured: includes an insurance status of "self-pay" and "no charge."

Encounters billed to the State Children's Health Insurance Program (SCHIP) may be classified as Medicaid, Private Insurance, or Other, depending on the structure of the State program. Because most State data do not identify SCHIP patients specifically, it is not possible to present this information separately.

When more than one payer is listed for a hospital discharge, the first-listed payer is used.

About HCUP

HCUP is a family of powerful healthcare databases, software tools, and products for advancing research. Sponsored by the Agency for Healthcare Research and Quality (AHRQ), HCUP includes the largest all-payer encounter-level collection of longitudinal healthcare data (inpatient, ambulatory surgery, and emergency department) in the United States, beginning in 1988. HCUP is a Federal-State-Industry Partnership that brings together the data collection efforts of many organizations—such as State data organizations, hospital associations, private data organizations, and the Federal government—to create a national information resource.

HCUP would not be possible without the contributions of the following data collection Partners from across the United States:

Alaska State Hospital and Nursing Home Association
Arizona Department of Health Services
Arkansas Department of Health
California Office of Statewide Health Planning and Development
Colorado Hospital Association
Connecticut Hospital Association
Florida Agency for Health Care Administration
Georgia Hospital Association
Hawaii Health Information Corporation
Illinois Department of Public Health
Indiana Hospital Association
Iowa Hospital Association
Kansas Hospital Association
Kentucky Cabinet for Health and Family Services
Louisiana Department of Health and Hospitals
Maine Health Data Organization
Maryland Health Services Cost Review Commission
Massachusetts Center for Health Information and Analysis
Michigan Health & Hospital Association
Minnesota Hospital Association
Mississippi Department of Health
Missouri Hospital Industry Data Institute
Montana MHA - An Association of Montana Health Care Providers
Nebraska Hospital Association
Nevada Department of Health and Human Services
New Hampshire Department of Health & Human Services
New Jersey Department of Health
New Mexico Department of Health
New York State Department of Health
North Carolina Department of Health and Human Services
North Dakota (data provided by the Minnesota Hospital Association)
Ohio Hospital Association
Oklahoma State Department of Health
Oregon Association of Hospitals and Health Systems
Oregon Health Policy and Research
Pennsylvania Health Care Cost Containment Council
Rhode Island Department of Health
South Carolina Budget & Control Board
South Dakota Association of Healthcare Organizations
Tennessee Hospital Association
Texas Department of State Health Services
Utah Department of Health
Vermont Association of Hospitals and Health Systems
Virginia Health Information
Washington State Department of Health
West Virginia Health Care Authority
Wisconsin Department of Health Services
Wyoming Hospital Association

About the NEDS

The HCUP Nationwide Emergency Department Sample (NEDS) is a unique and powerful database that yields national estimates of emergency department (ED) visits. The NEDS was constructed using records from both the HCUP State Emergency Department Databases (SEDD) and the State Inpatient Databases (SID). The SEDD capture information on ED visits that do not result in an admission (i.e., treat-and-release visits and transfers to another hospital); the SID contain information on patients initially seen in the emergency room and then admitted to the same hospital. The NEDS was created to enable analyses of ED utilization patterns and to support public health professionals, administrators, policymakers, and clinicians in their decision making regarding this critical source of care. The NEDS is produced annually beginning in 2006.

For More Information

For more information about HCUP, visit http://www.hcup-us.ahrq.gov/.

For additional HCUP statistics, visit HCUPnet, our interactive query system, at https://datatools.ahrq.gov/hcupnet.

For information on other hospitalizations in the United States, download HCUP Facts and Figures: Statistics on Hospital-Based Care in the United States in 2009, located at http://www.hcup-us.ahrq.gov/reports.jsp.

For a detailed description of HCUP, more information on the design of the Nationwide Emergency Department Sample (NEDS), and methods to calculate estimates, please refer to the following publications:

Introduction to the HCUP Nationwide Emergency Department Sample, 2010. Online. November 2012. U.S. Agency for Healthcare Research and Quality. http://hcup-us.ahrq.gov/db/nation/neds/NEDS2010Introductionv3.pdf. Accessed May 6, 2013.

Houchens R, Elixhauser A. Final Report on Calculating Nationwide Inpatient Sample (NIS) Variances, 2001. HCUP Methods Series Report #2003-2. Online. June 2005 (revised June 6, 2005). U.S. Agency for Healthcare Research and Quality. http://www.hcup-us.ahrq.gov/reports/methods/2003_02.pdf. Accessed May 6, 2013.

Suggested Citation

Villaveces A (RAND), Mutter R (AHRQ), Owens PL (AHRQ), Barrett ML (M. L. Barrett). Causes of Injuries Treated in the Emergency Department, 2010. HCUP Statistical Brief #156. May 2013. Agency for Healthcare Research and Quality, Rockville, MD. http://www.hcup-us.ahrq.gov/reports/statbriefs/sb156.pdf.

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AHRQ welcomes questions and comments from readers of this publication who are interested in obtaining more information about access, cost, use, financing, and quality of healthcare in the United States. We also invite you to tell us how you are using this Statistical Brief and other HCUP data and tools, and to share suggestions on how HCUP products might be enhanced to further meet your needs. Please e-mail us at hcup@ahrq.gov or send a letter to the address below:

Irene Fraser, Ph.D., Director
Center for Delivery, Organization, and Markets
Agency for Healthcare Research and Quality
540 Gaither Road
Rockville, MD 20850



¹ Centers for Disease Control and Prevention. Injury: The Leading Cause of Death Among Persons 1-44. Injury Prevention and Control. Updated March 14, 2013. https://www.cdc.gov/injury/wisqars/overview/key_data.html. Accessed May 6, 2013.
² Centers for Disease Control and Prevention. Saving Lives and Protecting People from Violence and Injuries. Injury Center. Updated November 27, 2012. www.cdc.gov/injury/pdfs/som_focusarea/NCIPC_FactSheet_O_v14.pdf. Accessed May 6, 2013.
³ Centers for Disease Control and Prevention. Injury Response. Injury Center. Updated September 8, 2011. Original source is no longer available on the Web; for related information, refer to: National Center for Injury Prevention and Control. CDC Injury Research Agenda, 2009-018. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention; 2009. https://stacks.cdc.gov/view/cdc/21769. Accessed November 8, 2017.
⁴Injury Surveillance Workgroup. Consensus Recommendations for Using Hospital Discharge Data for Injury Surveillance. Marietta (GA): State and Territorial Injury Prevention Directors Association; 2003. http://www.safestates.org/associations/5805/files/HospitalDischargeData.pdf. Please note that in 2010, the organizational name State and Territorial Injury Prevention Directors Association (STIPDA) was changed to Safe States Alliance.
⁵HCUP Cost-to-Charge Ratio Files (CCR). Healthcare Cost and Utilization Project (HCUP). 2001-2009. U.S. Agency for Healthcare Research and Quality, Rockville, MD. Updated September 2012. http://www.hcup-us.ahrq.gov/db/state/costtocharge.jsp. Accessed May 6, 2013.