Classifying external causes of injury: history, current approaches, and future directions.

The International Classification of Diseases (ICD) is used to categorize diseases, injuries, and external causes of injury, and it is a key epidemiologic tool enabling storage and retrieval of data from health and vital records to produce core international mortality and morbidity statistics. The ICD is updated periodically to ensure the classification system remains current, and work is now under way to develop the next revision, ICD-11. It has been almost 20 years since the last ICD edition was published and over 60 years since the last substantial structural revision of the external causes chapter. Revision of such a critical tool requires transparency and documentation to ensure that changes made to the classification system are recorded comprehensively for future reference. In this paper, the authors provide a history of the development of external causes classification and outline the external cause structure. They discuss approaches to manage ICD-10 deficiencies and outline the ICD-11 revision approach regarding the development of, rationale for, and implications of proposed changes to the chapter. Through improved capture of external cause concepts in ICD-11, a stronger evidence base will be available to inform injury prevention, treatment, rehabilitation, and policy initiatives to ultimately contribute to a reduction in injury morbidity and mortality.

Injury mortality indicators: recommendations from the International Collaborative Effort on Injury Statistics.

BACKGROUND: The International Collaborative Effort (ICE) on Injury Statistics called for an effort 'to reach consensus on what are the 10 most important indicators of injury incidence that offer the potential for international comparisons and for regional or global monitoring.' OBJECTIVES: To describe the process of developing the ICE indicators and to present the specifications of selected injury mortality indicators, along with comparisons between selected countries for those specified indicators. METHODS: Participants on the ICE list had been asked to send to one of the authors what they considered the most important five indicators of injury incidence. These were synthesised and presented under six themes: mortality indicators (general); mortality indicators (motor vehicle); mortality indicators (other); hospital data-based (overall); hospital data-based (traumatic brain injury (TBI)); long-term disability (overall). Following two work group discussions and after drafting and revising indicator specifications, agreement was reached on mortality indicators and specifications. Specifications for those mortality indicators are presented. Morbidity indicators are still to be agreed. RESULTS: The mortality indicators proposed were age-adjusted rates of injury death; motor vehicle traffic crash-related death; self-harm/suicide; assault/homicide; and TBI death. The empirical work highlighted difficulties in identifying TBI in countries where mortality data do not capture multiple injuries, prompting us to drop the mortality indicator related to TBI and moving us instead to introduce an indicator to monitor the use of undetermined intent in the classification of injury mortality. CONCLUSION: The ICE has reached a consensus on what injury mortality indicators should be used for comparison between countries. Specifications for each of these have been applied successfully to the mortality data of seven countries.

Availability and quality of cause-of-death data for estimating the global burden of injuries.

OBJECTIVE: To assess the availability and quality of global death registration data used for estimating injury mortality. METHODS: The completeness and coverage of recent national death registration data from the World Health Organization mortality database were assessed. The quality of data on a specific cause of injury death was judged high if fewer than 20% of deaths were attributed to any of several partially specified causes of injury, such as "unspecified unintentional injury". FINDINGS: Recent death registration data were available for 83 countries, comprising 28% of the global population. They included most high-income countries, most countries in Latin America and several in central Asia and the Caribbean. Categories commonly used for partially specified external causes of injury resulting in death included "undetermined intent," "unspecified mechanism of unintentional injury," "unspecified road injury" and "unspecified mechanism of homicide". Only 20 countries had high-quality data. Nevertheless, because the partially specified categories do contain some information about injury mechanisms, reliable estimates of deaths due to specific external causes of injury, such as road injury, suicide and homicide, could be derived for many more countries. CONCLUSION: Only 20 countries had high-quality death registration data that could be used for estimating injury mortality because injury deaths were frequently classified using imprecise partially specified categories. Analytical methods that can derive national estimates of injury mortality from alternative data sources are needed for countries without reliable death registration systems.

Injury episodes and circumstances: National Health Interview Survey, 1997-2007.

BACKGROUND: The National Health Interview Survey (NHIS) provides estimates of nonfatal, medically attended injuries and poisonings occurring in the United States. OBJECTIVES: The objectives of this report are to 1) document changes in the injury and poisoning section of NHIS from 1997 through 2007; 2) provide guidance on summarizing data across the 11-year study period; and 3) present detailed national estimates of nonfatal injury and poisoning episodes for the time period. DATA SOURCE: NHIS samples the civilian, noninstitutionalized population of the United States living in households. NHIS data from the years 1997-2007 were used in this report. Some questions related to injury and poisoning episodes were modified in 2000 and 2004. FINDINGS: During the period 1997-2004, many NHIS injury and poisoning questions were improved as a result of cognitive interviewing, data analysis, and feedback from interviewers and data users. Revisions to the NHIS injury and poisoning section pose some difficulties for trend analysis. However, some questions remained the same during the 11-year period, despite the questionnaire revisions. The injury and poisoning section has not been revised since 2004 and, where possible, analyses should be limited to 2004 and beyond. For analyses that require a longer time period, this report provides information on changes to questions and statistics that illustrate the effect of these changes on injury estimates. in 2007, the medically attended injury and poisoning episode rate among the U.S. civilian, noninstitutionalized population was 115.7 per 1,000 population. Despite differences in some questions during the period 1997-2007, NHIS data for these years show falls as the leading cause of injury and the home as the leading place that injury occurred.

Strategies to improve external cause-of-injury coding in state-based hospital discharge and emergency department data systems: recommendations of the CDC Workgroup for Improvement of External Cause-of-Injury Coding.

Each year, an estimated 50 million persons in the United States experience injuries that require medical attention. A substantial number of these persons are treated in an emergency department (ED) or a hospital, which collects their health-care data for administrative purposes. State-based morbidity data systems permit analysis of information on the mechanism and intent of injury through the use of external cause-of-injury coding (Ecoding). Ecoded state morbidity data can be used to monitor temporal changes and patterns in causes of unintentional injuries, assaults, and self-harm injuries and to set priorities for planning, implementing, and evaluating the effectiveness of injury-prevention programs. However, the quality of Ecoding varies substantially from state to state, which limits the usefulness of these data in certain states. This report discusses the value of using high-quality Ecoding to collect data in state-based morbidity data systems. Recommendations are provided to improve communication regarding Ecoding among stakeholders, enhance the completeness and accuracy of Ecoding, and make Ecoded data more useful for injury surveillance and prevention activities at the local, state, and federal levels. Implementing the recommendations outlined in this report should result in substantial improvements in the quality of external cause-of-injury data collected in hospital discharge and ED data systems in the United States and its territories.

Deaths: injuries, 2002.

OBJECTIVES: This report presents injury mortality data for 2002 using the external-cause-of-injury mortality matrix for the International Classification of Diseases, Tenth Revision (ICD-10). The external cause matrix is a detailed and comprehensive framework for tabulating and presenting injury deaths by mechanism and intent of death. Data are presented by age, sex, race, Hispanic origin, and State. In addition, trend data are shown for 1999-2002 by age, sex, and mechanism and intent of injury. This report also introduces the injury mortality diagnosis matrix. This latter is another framework that categorizes the nearly 1,200 injury diagnosis codes from ICD-10's chapter 19 according to body region and nature of the injury diagnosis information captured in the multiple-cause-of-death fields of the national mortality file. This report supplements the annual report of final mortality statistics. METHODS: Data in this report are based on information from all death certificates filed in the 50 States and the District of Columbia in 2002. Causes of death and nature of injury are processed and coded in accordance with the ICD-10. RESULTS: In 2002, 161,269 resident deaths occurred as the result of injuries. Of these injury deaths, 66.2 percent were classified as unintentional, 19.6 percent were suicides, 10.9 percent were homicides, 3.0 percent were of undetermined intent, and 0.3 percent involved legal intervention or operations of war. The five leading mechanisms of injury death were motor vehicle traffic, firearm, poisoning, falls, and suffocation, accounting for 81 percent of all injury deaths. The rate of poisoning deaths increased by 17.9 percent between 2001 and 2002, but the reader is advised to interpret these numbers cautiously as a portion of this increase is due to stricter procedures concerning data processing that were implemented in 2002. Thirty percent of injuries resulting in death were to the head and neck region with the vast majority of these classified as traumatic brain injury. Injuries involving the whole body system accounted for 28 percent of all injuries mentioned (17 percent were poisoning and 7 percent were other effects of external causes, such as submersion or asphyxiation). CONCLUSIONS: Injury mortality data presented in this report using the external cause-of-injury mortality matrix for ICD-10 provide detail on the mechanism of death needed for research and other activities related to injury prevention. This report highlights the importance of multiple causes-of-death data when analyzing injury mortality--special attention is given to the issue of accuracy and completeness of information as it pertains to these data. The Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics (NCHS) is involved in several ongoing projects related to the study of injury and injury mortality.

Injuries at work in the US adult population: contributions to the total injury burden.

OBJECTIVES: We estimated the contribution of nonfatal work-related injuries on the injury burden among working-age adults (aged 18-64 years) in the United States. METHODS: We used the 1997-1999 National Health Interview Survey (NHIS) to estimate injury rates and proportions of work-related vs non-work-related injuries. RESULTS: An estimated 19.4 million medically treated injuries occurred annually to working-age adults (11.7 episodes per 100 persons; 95% confidence interval [CI]=11.3, 12.1); 29%, or 5.5 million (4.5 per 100 persons; 95% CI=4.2, 4.7), occurred at work and varied by gender, age, and race/ethnicity. Among employed persons, 38% of injuries occurred at work, and among employed men aged 55-64 years, 49% of injuries occurred at work. CONCLUSIONS: Injuries at work comprise a substantial part of the injury burden, accounting for nearly half of all injuries in some age groups. The NHIS provides an important source of population-based data with which to determine the work relatedness of injuries. Study estimates of days away from work after injury were 1.8 times higher than the Bureau of Labor Statistics (BLS) workplace-based estimates and 1.4 times as high as BLS estimates for private industry. The prominence of occupational injuries among injuries to working-age adults reinforces the need to examine workplace conditions in efforts to reduce the societal impact of injuries.

Deaths: injuries, 2001.

OBJECTIVES: This report presents injury mortality data for 2001 using the external cause of injury mortality matrix for the International Classification of Diseases, Tenth Revision (ICD-10), a detailed and comprehensive framework for tabulating and presenting injury deaths by mechanism and intent of death. Data are presented by age, sex, race, Hispanic origin, and State. This report also presents data on injury deaths classified according to the nature of the injury sustained. Deaths resulting from the terrorist attacks on September 11, 2001, are presented and the impact of these deaths on the trends in injury mortality is discussed. This report supplements the annual report of final mortality statistics. METHODS: Data in this report are based on information from all death certificates filed in the 50 States and the District of Columbia in 2001. Causes of death and nature of injury are processed and coded in accordance with the ICD-10. RESULTS: In 2001, 157,078 resident deaths occurred as the result of injuries. Of these injury deaths, 64.6 percent were classified as unintentional, 19.5 percent were suicides, 12.9 percent were homicides, 2.7 percent were of undetermined intent, and 0.3 percent involved legal intervention or operations of war. The five leading mechanisms of injury death were motor vehicle traffic, firearm, poisoning, falls, and suffocation, accounting for 78 percent of all injury deaths. A head injury was mentioned in 32 percent of injury deaths and was the most commonly mentioned injury condition resulting in death. Poisoning and toxic effects were the second most common, mentioned in 16 percent of injury deaths and were the underlying cause of 14 percent of injury deaths. In 2001, 36,753 deaths (1.6 percent of deaths) had a natural underlying cause of death but included one or more mentions of an external cause on the death certificate. CONCLUSIONS: Injury mortality data presented in this report using the external cause of injury mortality matrix for ICD-10 provide detail on the mechanism of death needed for research and other activities related to injury prevention. This report also highlights the importance of multiple causes of death when analyzing injury mortality data. The Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics (NCHS) is involved in several ongoing projects related to the study of injury and injury mortality.

International collaborative effort on injury statistics: 10-year review.

International comparisons of injury data may be useful for examining differences in risk and for suggesting potential interventions or hypotheses for future studies. However important issues to be considered in conducting comparisons are related to both the underlying quality of the data and how the data is collected. The International Collaborative Effort (ICE) on Injury Statistics grew out of concerns over the comparability of international injury data. This article outlines the history behind the development of the injury ICE, brief descriptions of current and past projects, collaborations, and reflections on the value of collaboration.

Firearm-related death and injury among children and adolescents.

As the articles in this journal issue show, gun violence affects children and youth in many ways: psychologically, emotionally, financially, and legally. But first and foremost, gun violence affects children's physical safety. Therefore, this issue opens with an overview of the physical toll that firearms exact upon children and youth, reviewing the incidence of firearm-related injury and death among Americans under age 20. This article analyzes trends and current status in firearm death and injury, based on nationwide data collected by the federal government. Several key findings emerge from the data: Firearm death rates among children and youth in the United States have declined dramatically since 1993, but remain high compared with historical rates in this country and rates in other developed nations. A majority of these deaths are homicides. Certain groups of children and youth, especially adolescents, boys, minority youth, and those residing outside the Northeast, are particularly at risk for firearm death. The problem is most acute among black teenage males. Firearm injuries are much more likely to result in death than are other injuries for which children and youth visit emergency departments--a reflection of the extreme lethality of firearms. Given these findings, the authors call for a concerted effort to reduce youth firearm deaths to levels comparable to those of other industrialized nations, using a wide variety of approaches that span the public health, criminal justice, and educational spheres. They also recommend improved data systems to track firearm injury and death, so that researchers can better analyze these incidents and evaluate intervention strategies.