access to the multiple cause-of-death data tapes. At this time, routine data on contributing causes of injury death are not published.

For morbidity, the clinical modification of the ICD-10, currently under development, should improve its specificity regarding the extent and severity of the injury. These codes are widely used by health care providers throughout the United States, and are included in most administrative databases and registries. However, there has been little guidance from the injury field as to their optimal use in surveillance and research. The International Collaborative Effort for Injury Statistics (ICE) is currently developing recommendations for presenting injury morbidity data using the ICD nature-of-injury codes (L. Fingerhut, NCHS, personal communication, 1998).

Coding the Causes of Injury

The ICD-9 Supplementary Classification of External Causes of Injury and Poisoning (E codes) summarizes the circumstances causing the injury, including the intent (intentional and unintentional) and mechanism (e.g., falls, motor vehicle crashes, firearms) of the injury. For mortality data, coding guidelines indicate the use of an external cause-of-injury code as the underlying cause of death when the morbid condition is classifiable to an injury diagnosis.

For morbidity data, the 1990s have witnessed major advances in coding because of the increasing availability of external cause-of-injury codes in health systems data. In 1991, the National Committee on Vital and Health Statistics issued a series of recommendations regarding the use of E-codes. These included a recommendation that ''whenever an injury is the principal diagnosis or directly related to the principal diagnosis for a hospitalized patient, there should be an external cause of injury recorded in the medical record" (NCHS, 1991).

Since 1992, the Emergency Department Component of the National Hospital Ambulatory Medical Care Survey (NHAMCS) has routinely included E-codes (Burt and Fingerhut, 1998). The National Ambulatory Medical Care Survey (NAMCS) added E-codes in 1995 and the format of the redesigned National Health Interview Survey (NHIS) in 1997 will facilitate the data being E-coded. Currently, 23 states have mandated that E-codes be included in their hospital discharge data systems; 9 states have mandated E-coding of all emergency department encounters (Annest et al., 1998). A new framework for presenting E-coded injury data promises to expedite comparisons of injury profiles across populations and regions (CDC, 1997).

Despite its usefulness for the general categorization of injuries by mechanism and intent, significant limitations of the ICD-9 E-code classification have been noted (Fingerhut and Cox, 1998; Smith and Langley, 1998). In response, the tenth revision of the ICD has made some notable improvements, including the addition of requisite codes for place of occurrence and activity in which the



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