Injury-Related Hospitalizations and Emergency Department (ED) Visit Definitions

Injury Hospitalization and ED Rates

The injury hospitalization and ED rates are calculated by dividing the number of injury-related visits per year by the population. It is usually expressed as the number of injuries per 100,000 population. The rate may refer to injury visits in a specific group, or to injury visits from a specific cause, or to all injury visits in the entire population. The rate may be adjusted for the age composition of the group or it may be the observed (or "crude") rate. This module uses the patient's county of residence for the population base.

Age Adjustment

Age adjustment enhances the comparability of populations by controlling for the effects of their differing age compositions. It does this by applying age-specific rates in a population of interest to a standardized age distribution. The age-adjusted rates for two populations can be compared at the same point in time or the age-adjusted rates for the same population may be compared at different points in time. Age-adjusted rates in WISH are calculated using the direct method and are based on the year 2000 Standard U.S. Population.

Hospitalization Discharge Status

The discharge status indicates the place or circumstances to which the inpatient is discharged or transferred when released. It is coded by the hospital. Patient discharge status codes are defined by the Centers for Medicare and Medicaid Services for the Uniform Billing form.

E-code or External Cause of Injury

The external underlying cause of injury is the way in which the person sustained the injury; how the person was injured; or the process by which the injury occurred. External causes for injuries are coded from the medical record by hospital staff according to the International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM), and Tenth Edition, Clinical Modification (ICD-10-CM).

Manner or Intent of Injury

The E-code system captures both the external cause of an injury and the manner in which it occurred or the intent of the person causing it. Most injuries are the result of unintentional circumstances or events.

Expected Primary Payer

The payer who is expected by the hospital to be the primary payer. This payer will be the first one billed. There also may be a secondary payer.

Hospital or ED Charges

Total and average charges include only the hospital or ED charges. They do not include any separate fees for physicians, anesthetists, and other professionals. This is not the same as the costs to the payer, since private insurers, Medicaid and Medicare only reimburse the hospital for some fraction of the charges billed.

Rates by Race/Ethnicity

The population estimates used as denominators for the injury hospitalization rates in WISH are based on the bridged race estimates provided by the U.S. Census Bureau and the National Center for Health Statistics (NCHS). The estimates have been controlled so they sum to the annual estimates published by the Office of Health Informatics.

Producing the bridged race estimates was necessary because race categories in Census 2000 differed from those used in previous years. Specifically, data on race from Census 2000 were not directly comparable to data from previous years due, in large part, to giving respondents the option to report more than one race.

As a result, NCHS and the Census Bureau produced bridged race estimates that allow calculation of rates by race/ethnicity across years. These estimates distribute (or "bridge") the "more than one race" and "some other race" populations into one of four major race groups (American Indian/Alaska Native, Asian/Pacific Islander, Black, and White) and two ethnicity groups (Hispanic/Latino, non-Hispanic/Latino).

NCHS and the Census Bureau have produced this set of bridged race estimates extending back to the 1990 Census, and plan to produce these estimates on an annual basis in the future. WISH will be updated each year as these estimates become available.

Last Revised: September 26, 2018