This help file section provides a detailed description of the purpose of and data sources for WISQARS Fatal as well as the procedures involved in processing the data.  The topics include

6.1 Purpose and Intended Audience of WISQARS Fatal 

6.2 Mortality (Fatal Injury) Data

6.3 Coding of Data

• 6.3.1  1999 and Later Data
• 6.3.2  1998 and Earlier Data

6.4 Population Estimates

6.5 Availability of New Data

6.6 Citing Data Presented by WISQARS Fatal

 
WISQARS Fatal provides mortality data, focusing on mortality data related to injury.  This data is intended for a broad audience--the public, the media, public health practitioners and researchers, and public health officials--to increase their knowledge of injury.  The data provides information about what types of injuries are leading causes of deaths, how common they are, and who they affect.  In addition, the mortality data help federal, state, and local public health officials to 

• characterize and monitor injury trends, 
• identify persons at risk, and
• provide reliable surveillance data for program and policy decisions.

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WISQARS Fatal's mortality reports provide tables of the total numbers of injury-related deaths and the death rates per 100,000 population.  The reports lists deaths according to cause (mechanism) and intent (manner) of injury by state, race, Hispanic origin, sex, and age groupings.

Mortality data come from the National Center for Heath Statistics (NCHS), CDC annual mortality data files. NCHS mortality data are derived from the Multiple Cause of Death data.¹  For more information, contact NCHS at (301)436-8500 or nchsquery@cdc.gov -- or visit the NCHS website. 

The system calculates age-adjusted rates by the direct method and standardizes them to the total U.S. population.  You may select one of five standard years: 1940, 1970, 1980, 1990, and 2000.  Using 1940 as a standard year is consistent with data reported by National Center for Health Statistics (NCHS).  Using 1940 and 2000 also is consistent with data being tracked for the year 2000 objectives of the U.S. Public Health Service.²  WISQARS Fatal's age-adjusted death rates may differ slightly from those of NCHS.  WISQARS uses 5-year age categories for calculations while NCHS used 10-year age groups.¹

For your convenience, WISQARS provides death and death rate data for as many categories as possible. However, be advised NCHS considers rates based on 20 or fewer deaths to be statistically unreliable. For further details on reliability and other statistical issues, please refer to the National Vital Statistics Report, 1998.¹  (To obtain a copy of this report, contact NCHS at (301)436-8500 or nchsquery@cdc.gov -- or visit the NCHS website.) 

Between 1989-1995, some states' annual counts of deaths differed from those of NCHS. Differences between state and NCHS counts occur among selected causes of death, principally symptoms, signs, and ill-defined conditions (ICD-9 Nos. 780-799) and external causes (homicides, suicides and unintentional injuries). These differences happened mainly because NCHS did not receive changes from modified death records. The states affected were Alaska, 1989-1995; Alabama, 1991-1992; Hawaii, 1991; and New Jersey, 1991-1993.³

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Since 1999, mortality data has been coded using International Classification of Disease-10th Revision (ICD-10). Mechanism and cause of injury are based on ICD-10 external cause of injury codes. These codes are no longer considered supplemental codes as they were in ICD-9, and they are no longer referred to as "E-codes." The external cause of injury codes have been incorporated into the ICD-10 alphanumeric classification system as Chapter 20. ICD-10 external cause of injury codes begin with the letter V, W, X, or Y followed by a two-digit whole number (e.g., W25). Some external cause of injury codes also have a decimal followed by another number (e.g., V30.4).

Be aware that ICD-10 is a completely different coding system than ICD-9. Cause (mechanism) of injury categories defined using ICD-9 E-codes for deaths in 1981 through 1998 are different from those defined by ICD-10 external cause of injury codes for deaths in 1999. ICD-10 has many changes from ICD-9, including considerably greater detail; shifts of inclusion terms and titles from one category section or chapter to another; regroupings of diseases; new titles and sections; and modifications in coding rules.³ National Center for Health Statistics does not recommend combining 1999 and later data in WISQARS with previous years by cause (mechanism) categories to obtain average annual numbers of death and death rates. Also, when looking at trends in annual numbers of deaths and death rates by mechanism/cause of injury, you should consider that changes in results from 1998 to 1999 could be a result of the change in code definitions and coding rules.¹

The Preliminary External Cause of Injury Mortality Matrix for ICD-10 is changed from the Recommended Framework for Presenting Injury Mortality data based on ICD-9 codes.^5,8,9  For example, the subcategory of "Bites and Stings" in the ICD-9 framework was dropped from the ICD-10 matrix because in ICD-10 "bitten by" has been combined with "contact with" and/or "struck by" for some relevant codes. Also, ICD-10 transportation-related codes have been expanded considerably, including the addition of a new category called "Other land transport."  To see other important changes, visit the NCHS web pages on the ICD-10 matrix.

Because of the distinct changes in code definitions and coding rules from ICD-9 to ICD-10, WISQARS Fatal presents mortality data for 1999 and beyond separately from data for 1998 and earlier.  NCHS is currently conducting an ICD-10 Comparability Study to assess the impact of the change to the new classification system.⁷  ICD-10 codes are being assigned to approximately 2.3 million resident deaths that occurred in the United States in 1996. These deaths have previously been coded using ICD-9. These dual-coded data can be used to calculate comparability ratios to adjust the number of deaths and death rates for 1999 based on ICD-10 so they will be comparable to the number of deaths and death rates based on ICD-9 for 1979 through 1998.

Change in WISQARS made on March 7, 2003 to accommodate revisions to the ICD-10 Injury Mortality Matrix
In December of 2002, NCHS revised the ICD-10 Injury Mortality Matrix to finalize groupings of ICD-10 external cause of injury classifications. These changes resulted in shifting of a few deaths from one transportation-related injury grouping to another. 

Among the transportation-related injury groupings in WISQARS, the following changes were made: 

• Codes were moved from the MV Traffic-Occupant category to the MV Traffic-Other category, and
• The following new groupings were added: Other Land Transport, Suicide; Other Land Transport, Homicide; Other Land Transport, Homicide/legal intervention; Other Land Transport, Violence-related; and Other Land Transport, Undertermined Intent.

These new groupings also affect the numbers of deaths and rates for the Overall Motor Vehicle grouping and subgroupings including: 

• Overall Motor Vehicle, Suicide
• Overall Motor Vehicle, Homicide
• Overall Motor Vehicle, Homicide/Legal Intervention
• Overall Motor Vehicle, Violence-Related
• Overall Motor Vehicle, Undetermined Intent.

Note: Table 5.1.1 : Valid Cause and Intent Combinations for 1999 and Later Data has been updated to reflect the shift in ICD-10 codes in the ICD-10 external cause of injury matrix for injury death data presented in WISQARS.

 

6.3.1 1999 and Later Data
All 1999 and later mortality statistics in WISQARS Fatal are based on codes in the International Classification of Disease-10th Revision (ICD-10).⁴ ICD-10 is used in various countries worldwide for coding death. The ICD-10 codes include code sets for types of disease, medical procedures, and external causes of injury. The numbers of deaths by external cause of injury were determined using the underlying cause of death codes from the annual mortality data file of the National Vital Statistics System, National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention.  For more information, visit the NCHS web page on mortality data.

WISQARS Fatal's available causes of injury are consistent with proposed standard ICD-10 external cause of injury groupings for reporting injury mortality data.⁵ NCHS has been collaborating with the National Center for Injury Prevention and Control (NCIPC) and members of the Injury Control and Emergency Health Services section of the American Public Health Association to develop these groupings.  WISQARS presents national mortality data by cause of death or mechanism of injury (e.g., fall, fire/flames, firearm, poisoning, and suffocation) and by intent or manner of death (e.g., suicide, homicide, unintentional injury).

Note: The external cause of injury coding for 1999 and later, based on the ICD-10 classification system, is notably different from external cause coding for 1998 and earlier years, based on the ICD-9 classification system. You may not be able to compare numbers of deaths and deaths rates computed for some external causes of injury based on 1999 and later data to those based on data from 1998 and earlier.  Consequently, use caution when doing trend analysis of numbers of deaths and death rates across these years. A comparability study to assess the effects of the change from ICD-9 to ICD-10 is underway by NCHS. Some preliminary comparability ratios are available from two reports: 

Hoyert DL, Arias E, Smith B, Murphy SL, Kochanek KD. Deaths: Final Data for 1999. National vital statistics reports; 49(8). Hyattsville, Maryland: National Center for Health Statistics; 2001. Available from URL: http://www.cdc.gov/nchs/data/nvsr/nvsr49/nvsr49_08.pdf 

Anderson RN, Minino AM, Hoyert DL, Rosenberg HM. Comparability of cause of death between ICD-9 and ICD-10: Preliminary estimates. National vital statistics reports; 49(2). Hyattsville, Maryland: National Center for Health Statistics; 2001. Available from:  http://www.cdc.gov/nchs/data/nvsr/nvsr49/nvsr49_02.pdf 
 

.6.3.2 1998 and Earlier Data 
All 1998 and earlier statistics in WISQARS Fatal are based on codes in the International Classification of Disease-9th Revision (ICD-9).⁴ ICD-9 is used in various countries worldwide in medical reports.  The ICD-9 codes include code sets for types of disease, injuries, and poisonings as well as external cause of injury (E codes). The numbers of deaths by external cause of injury come from annual mortality data of the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention. For more information, visit the NCHS web page on mortality data. 

WISQARS Fatal's available causes of injury are consistent with proposed standard ICD-9 code groupings for reporting injury mortality data.^5,7 CDC's National Center for Injury Prevention and Control (NCIPC) has been collaborating with NCHS and members of the Injury Control and Emergency Health Services section of the American Public Health Association to develop these groupings.  WISQARS Fatal displays national data by cause of death or mechanism of injury (e.g., fall, fire/flames, firearm, poisoning, and suffocation) and by intent or manner of death (e.g., suicide, homicide, unintentional injury).

Note: The external cause of injury coding for years 1999 and later, based on the ICD-10 classification system, is notably different from external cause coding for 1998 and earlier years, based on the ICD-9 classification system. You may not be able to compare numbers of deaths and deaths rates computed for some external causes of injury based on 1999 and later data to those based on data from 1998 and earlier.  Consequently, use caution when doing trend analysis of numbers of deaths and death rates across these years. A comparability study to assess the effects of the change from ICD-9 to ICD-10 is underway by NCHS. Some preliminary comparability ratios are available from two reports: 

Hoyert DL, Arias E, Smith B, Murphy SL, Kochanek KD. Deaths: Final Data for 1999. National vital statistics reports; 49(8). Hyattsville, Maryland: National Center for Health Statistics; 2001. Available at URL: http://www.cdc.gov/nchs/data/nvsr/nvsr49/nvsr49_08.pdf 

Anderson RN, Minino AM, Hoyert DL, Rosenberg HM. Comparability of cause of death between ICD-9 and ICD-10: Preliminary estimates. National vital statistics reports; 49(2). Hyattsville, Maryland: National Center for Health Statistics. 2001. Available at URL:  http://www.cdc.gov/nchs/data/nvsr/nvsr49/nvsr49_02.pdf 

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Resident population data used to calculate crude death rates and age-adjusted rates are from the U.S. Census Bureau. Population data from 1981 to 1989 are intercensal population estimates and the 1990 population data are from postcensal population estimates. The 1991-1999 data are from Bridged-Race Intercensal Population Estimates of the United States, July1 1991-July1, 1999. Beginning with year 2000, population figures are from Bridged-Race Postcensal Population Estimates of the United States for April 1, 2000, and July 1 for 2001 and beyond. These estimates were produced by the U.S. Census Bureau under a collaborative arrangement with the National Center for Health Statistics (NCHS). Theses estimates are relatively consistent with population estimates used by NCHS for calculating mortality rates based on data from the National Vital Statistics System. For more information about these population data, visit the National Center for Health Statistics website at www.cdc.gov/nchs/about/major/dvs/popbridge/popbridge.htm. Please note that postcensal population estimates are updated annually, which means that fatal injury rates from WISQARS prior to the update may be different.

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The mortality data reported in WISQARS^TM  Fatal and on National Center for Injury Prevention and Control web pages come from death certificate data reported to the National Center for Health Statistics (NCHS), CDC. NCHS collects, compiles, verifies and prepares these data for release to the public. The process takes approximately 18 months after the end of a given year. For example, 2003 mortality data will be available from NCHS in the third quarter (summer) of  2005.  Once the data are released, NCIPC require additional time to prepare the Web pages. You may expect to see 2003 mortality data available on WISQARS^TM the fourth quarter (fall) of 2005.

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To cite the results from WISQARS^TM in papers and other presentations, use the following text:

Centers for Disease Control and Prevention, National Centers for Injury Prevention and Control. Web-based Injury Statistics Query and Reporting System (WISQARS) [online]. (2005) {cited Year Month (abbreviated) Day}.  Available from: www.cdc.gov/ncipc/wisqars

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