Emergency Department Visit
Data

ED Injury Data: Step-by-Step Guide to Accessing NHAMCS-ED Public Use Data Files and Programs to Select Injury Records and Calculate Injury Visit Rates

• Data Source
• NHAMCS/ED-Injury Summary
• Publications
• Presentations
• Public Use Data

• Tools and Frameworks
• Links to Other Emergency Department Data
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• Contact Info

Data Source

National Hospital Ambulatory Medical Care Survey (NHAMCS), Emergency Department Visit Data

NHAMCS, Emergency Department - Injury Summary

Medical information about patient visits includes up to three reasons for the visit as expressed by the patient, up to three physician diagnoses, up to three external causes of injury (if visit was for an injury),  checklists of diagnostic/screening services and procedures ordered or provided, and up to six medications that were either ordered, supplied, administered, or continued at the visit. Diagnoses are coded using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM). Reasons for the visit and medications are coded using classification systems developed by NCHS.

The data collection instrument for this survey is a one-page questionnaire called the Patient Record Form.  Some data see Advance Data reports for each year for copies of the patient record form. 

Emergency department visits for injury are broadly defined in the NCHS publications of the Ambulatory Care Statistics Branch in order to reflect the burden of injury in the ED setting. However, injury visits are defined more narrowly in the Injury Fact Sheet  , in Health Data All Ages and in the forthcoming Injury Chartbook. The decision to narrow the scope was made by the Injury Team of the Special Projects Branch in the NCHS Office of Analysis and Epidemiology in an effort to make the definition of injury in an emergency department setting more comparable to what States are able to calculate. The more narrowly defined injury visit is an incidence-based rather than a burden-based measure. Thus, the definition of an injury visit includes initial visits for which there is either a 1^st listed injury diagnosis, or a valid external cause of injury code listed describing the circumstances of the injury event. Visits with a first-listed diagnosis describing a complication or adverse effect of medical care were excluded regardless of the external cause code. The relevant ICD-9-CM codes for injury diagnoses and for external causes of injury can be found in tables 2 and 3 of the report Consensus Recommendations for Using Hospital Discharge Data for Injury Surveillance . 

Publications

Recent NCHS Publications Using NHAMCS Injury Data:

Recommended Definition of Initial Injury Visits to Emergency Departments for Use With the NHAMCS-ED Data

National Hospital Ambulatory Medical Care Survey: 2004 Emergency Department Summary

Advance Data No. 372

This annual report describes ambulatory care visits to hospital emergency departments in the United States. The report contains the following tables related to injury and poisoning:

• Table 9. Number and percent distribution of emergency department visits with corresponding standard errors, by the 20 leading principal reasons for visit by patient: United States, 2004
• Table 12. Number and percent distribution of emergency department visits with corresponding standard errors, by the primary diagnosis: United States, 2004
• Table 15. Number, percent distribution, and annual rate of injury-related emergency department visits with corresponding standard errors, by patient's age, sex, and race: United States, 2004
• Table 15. Number and percent distribution of emergency department visits with corresponding standard errors by selected characteristics of the injury, according to patient's age: United States, 2004
• Table 16. Number and percent distribution of injury-related emergency department visits with corresponding standard errors by intent and mechanism of external cause: United States, 2004

National Hospital Ambulatory Medical Care Survey: 2001 Emergency Department Summary

Advance Data No. 335

Injury Visits to Hospital Emergency Departments: United States, 1992-95, Vital and Health Statistics

Series 13, No. 131

This report describes ambulatory care visits for injuries to hospital emergency departments in the United States. Statistics are presented on selected patient, hospital, and visit characteristics.

Recent NHAMCS publications available online

Other Publications Using NHAMCS Injury Data

Bull MJ, et al. Falls from heights: Windows, roofs, and balconies. Pediatrics 107(5):1188-91. May 2001.

Burt CW, Overpeck MD. Emergency visits for sports-related injuries. Ann Emerg Med 37:301-8.March 2001.

• Highlights: Average annual injury visits to hospital emergency departments by persons between 5 and 24 years of age by type of activity performed when injury occurred: United States, 1997-98

Chung KC, Spilson SV. The frequency and epidemiology of hand and forearm fractures in the United States. J Hand Surg [Am] 26(5):908-15. September 2001.

Guerrero JL, Thurman DJ, Sniezek JE. Emergency department visits associated with traumatic brain injury: United States, 1995-96. Brain Inj 14(2):181-6. February 2000.

Jager TE, Weiss HB, Coben JH, Pepe PE. Traumatic brain injuries evaluated in U.S. emergency departments, 1992-94. Acad Emerg Med 7(2):134-40. February 2000.

Mathers LJ, Weiss HB. Incidence and characteristics of fall-related emergency department visits. Acad Emerg Med 5(11):1064-70.November 1998.

McCaig LF, Burt CW, Stussman BJ. A comparison of work-related injury visits and other injury visits to emergency departments in the United States, 1995-96. J Occup Environ Med. 40(10):870-5. October 1998.

McCaig LF, Burt CW. Poisoning-related visits to emergency departments in the United States, 1993-96. Journal of Toxicology-Clinical Toxicology 37(7):817-26. 1999.

Miller TR, Cohen MA. Costs of gunshot and cut/stab wounds in the United States, with some Canadian comparisons. Accid Anal Prev 29(3):329-41. May 1997.

Phelan KJ, Khoury J, Kalkwarf HJ, Lanphear BP. Trends and patterns of playground injuries in United States children and adolescents. Ambulatory Pediatrics 1:(4)227-33. July-August 2001.

Powell EC, Tanz RR. Adjusting our view of injury risk: The burden of nonfatal injuries in infancy. Pediatrics 110(4):792-6. October 2002.

Powell EC, Tanz RR. Cycling injuries treated in emergency departments: need for bicycle helmets among preschoolers. Arch Pediatr Adolesc Med 2000 Nov;154(11):1096-100.

Singer AJ, Thode HC Jr. National analgesia prescribing patterns in emergency department patients with burns. J Burn Care Rehabil 23(6):361-5. November-December 2002.

Weiss HB, Friedman DI, Coben J. Incidence of dog bite injuries treated in emergency departments. JAMA 279:51-3 . 1998.

Presentations

National Hospital Ambulatory Medical Care Survey - ED Presentations

Public use data 

Public-use microdata files may be downloaded in ASCII format. These files generally require the use of statistical software such as SAS, SPSS, or Stata to read the data.  Downloadable data files and documentation are available for all survey years (1992-2005). Downloadable files for 1995-2005 include masked design variables needed for variance estimation software as well as SAS input, label, and format statements.  Similar enhancements will be made to earlier years of data as staff resources permit.  Stata and SPSS program statements are available for data years 2002-2005 (or most recent year).

We recommend basing ED rates on the U.S. civilian population.  Population data for estimated U.S. civilian population by single year of age and sex based on Census 2000 may be downloaded in SAS and Excel format for the years 1992-2005 (or most recent year).

Public-use data are also available on CD-ROM in Statistical Export and Tabulation Software (SETS) format. The CD-ROM version of the NHAMCS public-use files is accessed via SETS retrieval software included on the CD-ROM. SETS was developed by NCHS and uses a menu-driven system to generate user-defined tables. NHAMCS CD-ROMs contain single years of data. NHAMCS CD-ROMs are currently available for 1992-2002. Public-use data tapes are also available for all survey years through 1997. CD-ROMs and tapes can be obtained by contacting: Susan Schappert, e-mail: SSchappert@cdc.gov

Tools and Frameworks

Barell Matrix

The Barell Matrix is a two-dimensional array of three-, four-, and five-digit ICD-9-CM injury codes grouped by the body region of the injury and the nature of the injury and was developed by the International Collaborative Effort on Injury Statistics

ICD-9-CM Framework for Presenting Injury Morbidity Data-External Cause

This matrix contains the ICD-9-CM external cause of injury codes that are not included in ICD-9 mortality codes. In addition, a list of codes that have been added since 1994 is appended to the matrix.

Programs and Statements for Injury Data Analysis

NHAMCS-ED: SAS Statements for External Cause of Injury Matrix:

SAS statements for assigning external cause of injury codes to mechanism and intent of injury based on the ICD-9-CM external cause of injury matrix in NHAMCS-ED.

NHAMCS-ED: SAS Statements for Identifying Injury Records:
SAS statements for selecting 1st listed injury diagnosis and 1st listed E-code for defining an injury record in NHAMCS-ED

NHAMCS_ED: STATA Programs for Identifying Injury Records:

STATA program for selecting 1st listed injury diagnosis and 1st listed E-code for defining an injury record in NHAMCS-ED.

NHAMCS-ED: SAS and SUDAAN Programs for Variance Estimation:

Sample SAS and SUDAAN codes and documentation for variance estimation of complete NHAMCS-ED data.

Example of a SAS Program for Obtaining Frequencies of Injury Visit in NHAMCS-ED:

Sample SAS and SUDAAN programs that create weighted frequency counts for injury visit by age and gender and export to Excel file. You will need to modify the program to get the weighted frequencies for desired subpopulation, year, and age groups.

Links to Other Emergency Department Data

Emergency Department Information Systems Clearinghouse

National Trauma Data Bank

Links to Related Sites

Web-based Injury Statistics Query and Reporting System (WISQARS) Nonfatal - Provides national estimates from the National Electronic Injury Surveillance System-All Injury Program of nonfatal injuries treated in U.S. hospital emergency departments.

Listserv

Contact information

Linda McCaig
Phone: (301) 458- 4365
E-mail: lmccaig@cdc.gov

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National Center for Health Statistics
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Phone:
1-800-232-4636
nchsquery@cdc.gov

Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333, U.S.A
Tel: (404) 639-3311 / Public Inquiries: (404) 639-3534 / (800) 311-3435