Suggested citation

Heinen M, Hall MJ, Boudreault MA, Fingerhut LA.

National trends in injury hospitalizations, 1979-2001.

Hyattsville, Maryland: National Center for Health Statistics. March 2005.

National Trends in Injury Hospitalizations, 1979-2001 ii 

National Center for Health Statistics

Edward J. Sondik, Ph.D., Director

Jack R. Anderson, Deputy Director

Jennifer H. Madans, Ph.D., Associate Director for Science

Lawrence H. Cox, Ph.D., Associate Director for Research and Methodology

Edward L. Hunter, Associate Director for Planning, Budget, and Legislation

Michael H. Sadagursky, Associate Director for Management and Operations

Margot A. Palmer, Director for Information Technology

Phillip R. Beattie, Director for Information Services

Diane M. Makuc, Dr.P.H., Associate Director for Analysis and Epidemiology

Charles J. Rothwell, Director for Vital Statistics

Jane E. Sisk, Ph.D., Director for Health Care Statistics

Jane F. Gentleman, Ph.D., Director for Health Interview Statistics

Clifford L. Johnson, Director for Health and Nutrition Examination Surveys

Office of Analysis and Epidemiology

Diane M. Makuc, Dr.P.H., Associate Director for Analysis and Epidemiology

Lois A. Fingerhut, Special Assistant for Injury Epidemiology

Division of Health Care Statistics

Jane E. Sisk, Ph.D., Director

Irma Arispe, Ph.D., Associate Director for Science

Robert Pokras, Chief, Hospital Care Statistics Branch
National Trends in Injury Hospitalizations, 1979-2001 iii

The chartbook was prepared by Melissa Heinen, Margaret Jean Hall, Manon A. Boudreault, and Lois A. 

Fingerhut with assistance from Rong Cai, Stephanie Furr, and Margaret Warner. Analytic assistance 

was provided by Jennifer Parker. The chartbook was reviewed by Irma Arispe, Diane Makuc, Jennifer 

Madans, and Robert Pokras1.

Publications management and editorial review were provided by Thelma W. Sanders. The design and 

graphics were supervised by Sarah Hinkle. Printing was managed by Patty L. Wilson.

1Manon A. Boudreault, Lois A. Fingerhut, Margaret Warner, Jennifer Parker, Stephanie Furr, and Diane 

Makuc are in the Office of Analysis and Epidemiology (OAE); Melissa Heinen worked in OAE, National 

Center for Health Statistics (NCHS) until December 2003. Margaret Jean Hall, Rong Cai, Irma Arispe, 

and Robert Pokras are in the Division of Health Care Statistics. Jennifer Madans is the Associate 

Director for Science, NCHS.

Acknowledgments
National Trends in Injury Hospitalizations, 1979-2001 v

Contents

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iii

List of Figures and Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Chartbook on Trends in Injury Hospitalizations: United States, 1979–2001

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

General Statistics

Injury and Noninjury Discharges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Injury Hospital Discharge Rates by Sex and Race . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Injury Hospital Discharge Rates by Sex and Age . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Injury Diagnoses and External Causes of Injury

Barell Matrix for Injury Diagnosis Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Discharges by Injury Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Poisoning and Toxic Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Discharges by Body Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Extremity Injuries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Head and Neck Injuries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Hip Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

External Cause of Injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Utilization and Payment

Average Number of Diagnoses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Days of Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Average Length of Stay by Age and Sex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Average Length of Stay by Injury Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Discharge Disposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Discharge Disposition by Age . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Expected Source of Payment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Appendixes

A. Data Sources, Definitions, and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

B. The Barell injury diagnosis matrix; classification by body region and nature of injury . . . . . . . 104

C. Recommended framework of E-code groupings for presenting injury morbidity data . . . . . . . . 105
National Trends in Injury Hospitalizations, 1979-2001 vii

List of Figures and Tables 

Text Tables

1. Diagnosis labels and ICD-9-CM codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2. External cause code definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 1. Number of hospital discharges by first-listed diagnosis, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 2. Hospital discharge rates by first-listed diagnosis, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Data table for figures 1 and 2. Hospital discharges for injury and noninjury diagnoses, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 3. Injury hospital discharge rates by sex, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 4. Injury hospital discharge rates by race and sex, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Data table for figure 3. Injury hospital discharges by sex, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Data table for figure 4. Injury hospital discharges by race and sex, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

 Appendix table 4a. Number and percent reporting race among injury hospital discharges, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . 15

Figure 5. Injury hospital discharge rates among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 6. Injury hospital discharge rates among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Data table for figure 5. Injury hospital discharges among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Data table for figure 6. Injury hospital discharges among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Figure 7. Barell Matrix: Injury hospital discharge rates by nature of injury and body region, 1979–1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 8. Barell Matrix: Injury hospital discharge rates by nature of injury and body region, 1998–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 9. Hospital discharge rates by nature of injury diagnosis, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Data table for figure 9. Injury hospital discharges by nature of injury diagnosis, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

 Appendix table 9a. Percent distribution of injury hospital discharges by nature of injury diagnosis, 1979–2001 . . . . . . . . . . . . . . . . 24

 Appendix table 9b. Internal organ injury hospital discharges among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

 Appendix table 9c. Internal organ injury hospital discharges among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . 26

 Appendix table 9d. Percent distribution of system wide injury hospital discharges by diagnosis, 1979–2001 . . . . . . . . . . . . . . . . . . 27

Figure 10. Fracture hospital discharge rates among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Figure 11. Fracture hospital discharge rates among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Data table for figure 10. Fracture hospital discharges among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Data table for figure 11. Fracture hospital discharges among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 12. Poisoning and toxic effects hospital discharge rates among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 13. Poisoning and toxic effects hospital discharge rates among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Data table for figure 12. Poisoning and toxic effects hospital discharges among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . 33

Data table for figure 13. Poisoning and toxic effects hospital discharges among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . 34

 Appendix table 12a. Poisoning and toxic effects hospital discharges by diagnosis, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Figure 14. Injury hospital discharge rates by body region of injury, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Data table for figure 14. Injury hospital discharges by body region of injury, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
National Trends in Injury Hospitalizations, 1979-2001 viii 

List of Figures and Tables 

 Appendix table 14a. Injury hospital discharges by body region of injury, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

 Appendix table 14b. Torso injury hospital discharges among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

 Appendix table 14c. Torso injury hospital discharges among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Figure 15. Extremity injury hospital discharge rates among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Figure 16. Extremity injury hospital discharge rates among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Data table for figure 15. Extremity injury hospital discharges among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Data table for figure 16. Extremity injury hospital discharges among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

 Appendix table 15a. Upper extremity injury hospital discharges among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . 45

 Appendix table 15b. Other lower extremity injury hospital discharges among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . 46

 Appendix table 16a. Upper extremity injury hospital discharges among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . 47

 Appendix table 16b. Other lower extremity injury hospital discharges among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . 48

 Appendix table 16c. Extremity injury hospital discharges by body region, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Figure 17. Head and neck injury hospital discharge rates among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Figure 18. Head and neck injury hospital discharge rates among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Data table for figure 17. Head and neck injury hospital discharges among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Data table for figure 18. Head and neck injury hospital discharges among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

 Appendix table 17a. Traumatic brain injury hospital discharges among males by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . 53

 Appendix table 18a. Traumatic brain injury hospital discharges among females by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . 54

Figure 19. Hip fracture hospital discharge rates among females 65 years and over by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Data table for figure 19. Hip fracture hospital discharges among females 65 years and over by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . 57

 Appendix table 19a. Extremity fracture hospital discharges among females 65 years and over by body region, 1979–2001 . . . . . . . . 58

Figure 20. Percent distribution of injury hospital discharges by mechanism, 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Figure 21. Percent distribution of injury hospital discharges by intent, 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Figure 22. Percent of injury hospital discharges with an external cause of injury code, by nature of injury diagnosis and body region of injury, 2001 . . 61

Data table for figure 20. Injury hospital discharges by mechanism, 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Data table for figure 21. Injury hospital discharges by intent, 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Data table for figure 22. Injury hospital discharges with an external cause of injury code, by nature of injury diagnosis

and body region of injury, 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

 Appendix table 20a. Injury hospital discharges with an external cause of injury code, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . 63

 Appendix table 20b. System wide injury hospital discharges by mechanism and intent, 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

 Appendix table 20c. Fracture hospital discharges by mechanism, 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

 Appendix table 20d. Poisoning and toxic effects hospital discharges by intent, 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

 Appendix table 20e. Poisoning and toxic effects hospital discharges by mechanism, 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

 Appendix table 20f. Injury hospital discharges with an external cause of injury code by selected patient characteristics, 2001 . . . . . . 64

Figure 23. Average number of diagnoses among injury hospital discharges, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Data table for figure 23. Average number of diagnoses for injury and noninjury hospital discharges, 1979–2001 . . . . . . . . . . . . . . . . . . . . . 67

 Appendix table 23a. Total number of diagnoses coded for injury hospital discharges, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . 68
National Trends in Injury Hospitalizations, 1979-2001 ix

List of Figures and Tables 

Figure 24. Number of days of care for injury and noninjury hospital discharges, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Data table for figure 24. Number of days of care for injury and noninjury hospital discharges, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . 70

 Appendix table 24a. Number of days of care for injury hospital discharges by nature of injury diagnosis, 1979–2001 . . . . . . . . . . . . 71

 Appendix table 24b. Number of days of care for injury hospital discharges by body region of injury, 1979–2001 . . . . . . . . . . . . . . . . 72

Figure 25. Average length of stay in days for injury hospital discharges by age, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Figure 26. Average length of stay in days for injury hospital discharges by sex, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Data table for figures 25 and 26. Average length of stay in days for injury hospital discharges by age and sex, 1979–2001 . . . . . . . . . . . . . 75

 Appendix table 25a. Average length of stay in days among injury and noninjury hospital discharges, 1979–2001 . . . . . . . . . . . . . . . 76

Figure 27. Average length of stay in days for injury hospital discharges by diagnosis, 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Data table for figure 27. Average length of stay in days for injury hospital discharges by diagnosis, 1979–2001 . . . . . . . . . . . . . . . . . . . . . 79

Figure 28. Percent distribution of injury hospital discharges by selected discharge disposition, 1981–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Data table for figure 28. Injury hospital discharges by selected discharge disposition, 1981–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Figure 29. Percent of injury hospitalizations discharged home by age, 1981–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Figure 30. Percent of injury hospitalizations discharged to a long-term care institution by age, 1981–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Data table for figures 29 and 30. Injury hospital discharges among selected discharge dispositions by age, 1981–2001 . . . . . . . . . . . . . . . . 83

Figure 31. Percent distribution of injury hospital discharges among those under 65 years of age by principal expected source of payment, 1979–2001 . . 84

Data table for figure 31. Injury hospital discharges among those under 65 years of age by principal expected source of payment, 1979–2001 . . 85

 Appendix table 31a. Injury hospital discharges among those 65 years of age and over by principal expected source of payment,

 1979–2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
National Trends in Injury Hospitalizations, 1979-2001 1

In 2001

• In 2001 injuries accounted for 1.8 million hospital discharges or 64.2 discharges per 10,000

population, and injuries accounted for 9 million days of inpatient care. (figures 1, 2, and 24)

• In 2001, 68 percent of injury discharges had an external cause code; of these, unintentional injuries 

were the majority. Falls, poisonings, and motor vehicle traffic-related injuries were the leading

external causes of injuries regardless of intent. (figures 20–22)

From 1979 to 2001

• In 2001 injury discharges accounted for 6 percent of all short-stay hospital discharges, down from 9 

percent in 1979. (figure 1)

• From 1979 to 2001 the discharge rate for injuries decreased on average 4.3 percent per year, and 

the total number of days of inpatient care for injuries decreased on average 5.2 percent per year.

(figures 2 and 24)

• Injury hospital discharge rates were generally higher for males than for females under 65 years of 

age; however, females 65 years of age and over had higher injury discharge rates than males. From 

the early 1980s to 2001, females 65 years of age and over had the highest rate of injury discharges of 

any age/sex group although the overall rates for women 65 years and over decreased on average 0.6 

percent per year. (figures 5 and 6)

• Fractures were the leading cause of injury hospitalizations, accounting for 36 percent of all injury 

hospital discharges in 1979 and 55 percent in 2001. The highest discharge rate was among females 

65 years of age and over. (figures 9 and 11)

• Poisoning and toxic effects accounted for 6 percent of all injury hospital discharges in 1979 and 11 

percent in 2001. (figures 12 and 13)

• Extremity injury discharge rates were higher than the rates for the other body regions and declined, 

on average, 3.4 percent per year. The highest discharge rates were consistently among females 65 

years of age and over. (figures 14 and 16)

• Discharge rates for head and neck injuries for males and females under 65 years of age decreased 

on average 4.0 to 7.6 percent per year. From 1979 to 2001 traumatic brain injuries accounted for 

about 50–70 percent of all head and neck injuries. (figures 17 and 18)

• Hip fractures were most common among females 65 years of age and over. Females 85 years and 

over had the highest discharge rate for hip fracture, and the discharge rate for this group increased on 

average 0.7 percent per year. (figure 19)

Highlights
National Trends in Injury Hospitalizations, 1979-2001 2 

• The average length of stay for injury hospitalizations among those 65 years of age and over decreased on 

average 4.4 percent per year, while the average decrease for those under 65 years of age was 1.9 percent per 

year. (figure 25)

• From 1981 to 2001 the percent of injury hospitalizations discharged home among those 65 years of age and 

over decreased on average 4 percent each year compared with those under 65 years of age for whom the percent decreased on average 0.5 percent each year. The percent discharged to a long-term care institution and 

to a short-term facility increased for both age groups. (figures 28–30)

• In 2001 private insurance was the principal expected source of payment for about one-half of injury patients 

under 65 years of age. However, from 1979 to 2001, the proportion of injury discharges covered by Medicare, Medicaid, and the uninsured increased while the proportion paid by private health insurance decreased. 

(figure 31)

Highlights
National Trends in Injury Hospitalizations, 1979-2001 3

Medical expenditures for injury remained relatively constant from 1985 to 2000 and were estimated in 

2000 at $117 billion (1–3)§ accounting for 10.3 percent of total medical expenditures. Expenditures 

per injured person were approximately $2,600 and nearly $430 per capita (1). In 1995 the total 

cost of injury was estimated at $1.7 trillion, including work loss, direct costs, and costs for pain and 

suffering (2).

In 2001 injuries accounted for 157,000 deaths (4), 1.8 million hospitalizations, 9 million days of 

inpatient care (5), and 33.8 million emergency department visits (6). This report describes trends in 

injury hospitalizations. National data on injury deaths, emergency department visits and episodes of 

injuries are available from other National Center for Health Statistics (NCHS) sources (7–9) as well as 

from other Federal and non-Federal sources (10).

Data on fatal and nonfatal injuries are used by public health officials and researchers to monitor 

trends, measure risk factors, evaluate the effectiveness of existing policies and programs, and assess 

the need for new policies and programs. In addition, data on injuries are used in monitoring progress 

toward achieving the Healthy People 2010 Injury-Related Objectives for the Nation (11).

Until recently there has not been a uniform method for analyzing and reporting injury hospital 

discharge data; thus, comparisons of hospital discharge rates for injuries within and across States and 

other jurisdictions were problematic. To help standardize injury hospital discharge data, the State 

and Territorial Injury Prevention Directors Association (STIPDA), in collaboration with other State 

and Federal agencies, released a report, Consensus Recommendations for Using Hospital Discharge 

Data for Injury Surveillance (12). The report recommended standard International Classification 

of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) categories and methods for analyzing 

and reporting injury hospital discharge data. This chartbook is the first application of the STIPDA 

recommendations to national level data. In addition to providing broad measures for the United 

States, national level data are valuable as a benchmark for States and localities.

Methods

Data from 23 years, 1979 through 2001, of the National Hospital Discharge Survey (NHDS) are 

analyzed for this report. The NHDS is a nationally representative survey of discharges from nonFederal short-stay hospitals in the United States. “Appendix A” includes a detailed description of 

the NHDS. Since 1979, ICD-9-CM has been used for coding diagnoses and procedures in the NHDS 

(13). There were a small number of ICD-9-CM coding changes over the study period, but they only 

minimally affected the total number of injury discharges (“Appendix A,” ICD-9-CM addenda affecting 

injuries). Chapter 17 of the ICD-9-CM includes the diagnosis codes for injury. Codes for external 

causes of injury are in the Supplementary Classification of External Causes of Injury and Poisoning 

section of ICD-9-CM. Codes used in this report are listed in tables 1 and 2.

Introduction

§ The 1985 estimate used for comparison is inflation-adjusted to year 2000 dollars. The 1985 actual estimate was $45 

billion. The 1995 inflation-adjusted estimate based on 2000 dollars was $109 billion ($91 billion actual dollars) (2–3 and 

T. Miller, personal communication, January 2004).
National Trends in Injury Hospitalizations, 1979-2001 4 

Table 1. Diagnosis labels and ICD-9-CM codes

Category Principal diagnosis (first-listed diagnosis)

ICD-9-CM diagnosis codes included

All discharges 001-999, V01-V82

Injury1 (as defined by STIPDA) 800-909.2, 909.4, 909.9, 910-994.9, 995.5-995.59,

995.80-995.85

Noninjury

Complications of care and adverse effects (and their late

effects)

909.3, 909.5. 995.0-995.4, 995.6-995.7, 995.86,

995.89, 996-999

All other 001-799, V01-V82

1Unless otherwise specified “injury” diagnoses include poisoning.

NOTE: See “Appendix B” for ICD-9-CM codes and labels.

Table 2. External cause code definition

All injury and poisoning external cause codes

(as defined by ICD-9-CM)

E800-E999 (ICD-9-CM Supplementary Classification of 

External Causes of Injury and Poisoning)

Injury and poisoning external cause codes as

defined by the External cause of injury matrix

and used for figures 20-22

E800-E848, E850-E868, E869.0-E869.3, E869.8-E869.9,

E880-E929, E950-E966, E968-E999

NOTE: See “Appendix A,” External cause of injury code, and “Appendix C,” ICD-9-CM External Cause of Injury Matrix.

The STIPDA recommended case definition for injury hospitalizations was used to define injuries for this 

chartbook and is based on the first-listed diagnosis. The injury codes include ICD-9-CM 800-909.2, 

909.4, 909.9, 910-994.9, 995.5-995.59, 995.80-995.85 (12). Excluded from the recommended 

definition are the codes for complications of care and adverse effects as well as their late effects (12) 

(see table 1). Deaths in the hospital are included in this definition.

The STIPDA defined injuries were further categorized using the two-dimensional Barell Injury 

Diagnosis Matrix (14). One dimension is the body region of the injury, and the other dimension is 

the nature of the injury. A category of the matrix referred to as “system wide” injuries does not 

fit the two dimensional aspect of the matrix, but refers to conditions that are systemic, such as 

poisoning. The cells of the Barell Matrix contain ICD-9-CM codes from chapter 17 corresponding to 

the intersection of the dimensions of the matrix, and the codes are provided in “Appendix B.” A more 

thorough explanation of the matrix is in the Barell Matrix section of the chartbook and in “Appendix A,” 

Barell Matrix.

Introduction
National Trends in Injury Hospitalizations, 1979-2001 5

External causes of injury are defined and categorized using the two-dimensional ICD-9-CM External 

Cause Matrix (15,16). One dimension is the mechanism or external cause of the injury (e.g., fall, 

motor vehicle, etc.), and the other dimension is the manner or intent of the injury (e.g., self-inflicted, 

assault, unintentional, undetermined; see “Appendix A,” External Cause of Injury codes). The 

following external cause codes are included in the matrix: E800-E869 (excluding E849, E869.4), E880-

E929, E950-E999 (excluding E967) (see table 2). “Appendix C” includes the codes used to define 

each cell of the matrix. Exclusions include misadventures to patients during surgical and medical 

care and drugs, medicinal, and biological substances causing adverse effects in therapeutic use. 

Other exclusions are for invalid first-listed external cause codes (e.g., codes for place of occurrence 

or perpetrator of child or adult abuse) that should not be used without other external cause codes. 

If more than one ICD-9-CM external cause code was listed for a given record, only the first external 

cause code listed in the diagnostic code fields was used in this report. Coding guidelines recommend 

that the external cause code be related to the principal diagnosis as opposed to the initiating or 

underlying cause of the injury diagnosis (17). 

External cause of injury coding provides information on the circumstances and causes of injuries. For 

discharges with a first-listed injury diagnosis, external cause coding increased from 14 percent in 1979 

to 68 percent in 2001 (appendix table 20a); however, there has been no significant increase since 

1997. Much of the increase in external cause code recording on medical record abstracts is attributed 

to the increased number of States that mandate external cause codes (18). External cause of injury 

data in figures 20–22 are shown only for 2001 because the percent of injury discharges that were 

assigned an external cause code is relatively high, 68 percent, for this year. However, the percent 

without an external cause code is still substantial and as a result, analysis and interpretation of the 

data is somewhat limited. The data are still informative particularly in the absence of other more 

complete nationally representative data. 

Two measures are used in this report to present and discuss trends and changes in injury discharges 

in the United States from 1979 to 2001. The average annual percent change is calculated using 

weighted least squares regression. The average or total percent change from 1979 to 2001 is the 

average annual percent change multiplied by 22. Trends and differences were tested for statistical 

significance (see “Appendix A,” Average percent change over time, test of trend, and test of 

significance between two statistics). 

Estimates in all tables are rounded to the nearest thousand. Totals may include data for categories 

that are not shown individually in the tables. For these reasons, estimates within tables do not always 

add to the totals. Rates, percents, and average lengths of stay are calculated from unrounded figures 

and may not precisely agree with measures calculated from rounded data. Population denominators 

are for the civilian resident population.

Introduction
National Trends in Injury Hospitalizations, 1979-2001 6 

Organization of the Chartbook

Trends are graphically displayed by age and sex along with brief text highlights. Time trends are 

shown on a logarithmic scale to emphasize the rate of change and to enable measures with large 

differences in magnitude to be shown on the same figure (“Appendix A,” Logarithmic scale). Figures in 

this chartbook have been grouped into three sections:

1. General statistics by demographic information (figures 1–6)

2. Injury diagnoses and external causes of injuries (figures 7–22)

3. Utilization and payment (figures 23–31)

Following the figures in the chartbook are data tables for each figure that show the data points 

graphed and related appendix tables. Standard errors for the data points are also provided. Data 

points in the figures are either age-adjusted or age-specific rates, percents, or means (“Appendix A,” 

Age adjustment). 

When selecting figures for this chartbook, consideration was given to measures that illustrate the 

trends and demographic patterns for the leading injury diagnoses among inpatients in U.S. short-stay 

hospitals as well as patterns in utilization.

Trends in injury hospitalization should be considered within the context of overall hospitalization. For 

this reason this chartbook includes data on discharge rates, average numbers of diagnoses, days of 

care, and average lengths of stay for patients hospitalized for both injury and noninjury diagnoses. 

Discussion

In general, injury hospital discharge rates decreased from 1979 to 2001. It is important to 

understand that the decline reflects not only trends in the incidence of injury, but also changes in 

health care utilization and resources and the impact of new medical technologies (19). Partitioning 

the effects of each of these variables on injury hospitalization over time is beyond the scope of this 

chartbook. However, work is ongoing at the international level to develop measures of injury severity 

that will foster more valid and reliable surveillance of injury incidence (20).

A number of important changes in the health care delivery system led to decreases in hospitalization 

as a whole during the period from 1979 to 2001 including stricter utilization review that limited 

entry into the hospital, the growth of managed care that emphasized the avoidance of expensive 

hospitalization whenever possible, and the movement of a large proportion of diagnostic and surgical 

procedures from the inpatient to the outpatient setting (21–25). 

It was hypothesized that, in addition to these factors, hospitalization for injury would also be affected 

by numerous public and private sector efforts designed to decrease the occurrence and/or severity 

Introduction
National Trends in Injury Hospitalizations, 1979-2001 7

of unintentional and violence-related injuries. Included among these efforts were the widespread 

promotion and adoption of injury prevention activities such as the use of seat belts, safer automobiles 

(e.g., with air bags), improvements in road safety, requirements for helmet use for bicycles, 

motorcycles and in sports activities, efforts to improve home and workplace safety including access 

to poison control centers, and initiatives aimed at reducing assaults and self-directed harm and their 

resulting injuries (10). Most recently, attention is being directed to how hospitals can and should 

respond to mass trauma events with the aim of reducing the severity of the injuries (26).

Injury hospitalization data are important to track because such injuries, though rarely an immediate 

threat to life (only 2 percent of hospitalized injury patients die during their hospital stay), are 

generally serious enough to warrant acute inpatient care. The importance and expense of inpatient 

treatment has led most States to gather comprehensive data on injury hospitalization in their data 

systems. States will be able to compare the data they gather to the national data included in this 

chartbook. The data in this publication, along with data on the occurrence of, and health care 

treatment for, injuries in settings other than the hospital, can help States improve existing and design 

new injury prevention programs. 

Introduction
National Trends in Injury Hospitalizations, 1979-2001 8 

1. Centers for Disease Control and Prevention. Medical expenditures attributable to injuries in the U.S., 2000. MMWR 

53(01):1-4. 2004.

2. Miller T, Covington K, Jensen A. Costs of injury by major cause, United States, 1995: Cobbling together estimates in 

measuring the burden of injuries. In Mulder S and van Beeck EF, eds. Proceedings of a Conference in Noordwijkerhout, May 

13–15, 1998. Amsterdam: European Consumer Safety Association, 23–40. 1999.

3. Rice DP, MacKenzie EJ, Jones AS, et al. Cost of injury in the United States: A report to Congress. San Francisco, California: Institute for Health and Aging, University of California and Injury Prevention Center, The John Hopkins University. 

1989.

4. Arias E, Anderson RN, Hsiang-Ching K, Murphy SL, Kochanek KD. Deaths: Final data for 2001. National vital statistics 

reports; vol 52 no 3. Hyattsville, Maryland: National Center for Health Statistics. 2003.

5. Centers for Disease Control and Prevention. National Center for Health Statistics, National Hospital Discharge Survey, 

Public Use Data. 2001. See Table 1 for ICD-9-CM codes used to derive the number of discharges.

6. Based on data from the NHAMCS-ED data file. The number excludes visits for which either the first-listed injury diagnosis or first-listed external cause code for injury was an adverse event or complication of care. This definition, while not 

consistent with published numbers from NHAMCS, is consistent with the NHDS definition of injury used in this chartbook. 

For detail about the survey, see: McCaig LF, Burt CW. National Hospital Ambulatory Medical Care Survey: 2001 emergency 

department summary. Advance data from vital and health statistics; no 335. Hyattsville, Maryland: National Center for 

Health Statistics. 2003. 

7. Centers for Disease Control and Prevention. National Center for Health Statistics, Mortality Data http://www.cdc.gov/

nchs/about/major/dvs/mortdata.htm

8. Centers for Disease Control and Prevention. National Center for Health Statistics, National Ambulatory Medical Care Survey and National Hospital Ambulatory Care Survey. http://www.cdc.gov/nchs/about/major/ahcd/ahcd1.htm

9. Centers for Disease Control and Prevention. National Center for Health Statistics, National Health Interview Survey. http:

//www.cdc.gov/nchs/nhis.htm

10. Injury prevention research can be found at: SafetyLit Injury Prevention Update,

http://www.safetylit.org/search.htm

11. U.S. Department of Health and Human Services. Healthy People 2010. 2nd ed. With Understanding and Improving 

Health and Objectives for Improving Health. Vol II. Part B: Focus Area 15 - Injury and Violence Prevention. Washington, 

DC: U.S. Government Printing Office. 2000.

12. Injury Surveillance Workgroup. Consensus recommendations for using hospital discharge data for injury surveillance. 

Marietta, Georgia: State and Territorial Injury Prevention Directors Association; 2003. http://www.stipda.org/s-pubs/

hdd.pdf

13. International Classification of Diseases, 9th Revision, Clinical Modification, 6th Edition. U.S. Department of Health and 

Human Services, National Center for Health Statistics, Health Care Financing Administration. 1998. http://www.cdc.gov/

nchs/icd9.htm

14. Barell V, Aharonson-Daniel L, Fingerhut LA, MacKenzie EJ, et al. An introduction to the Barell body region by nature of 

injury diagnosis matrix. Inj Prev 8:91–6. 2002.

References
National Trends in Injury Hospitalizations, 1979-2001 9

15. Centers for Disease Control and Prevention. Recommended framework for presenting injury mortality data. MMWR 46 

(RR14):1–30. 1997. 

16. Centers for Disease Control and Prevention. Recommended framework of E-code groupings for presenting injury mortality and morbidity data. May 15, 2003.

http://www.cdc.gov/ncipc/whatsnew/matrix2.htm

17. ICD-9-CM Official Guidelines For Coding and Reporting, October 1, 2003.

http://www.cdc.gov/nchs/data/icd9/icdguide.pdf

18. Annest JL, Conn JM, McLoughlin E, Fingerhut LA, et al. How States are collecting and using cause of injury data. Report 

of the Data Committee of the Injury Control and Emergency Health Services Section of the American Public Health Association. 1998.

19. Pokras R, Kozak LJ, McCarthy E, Graves EJ. Trends in hospital utilization: United States, 1965–86. National Center for 

Health Statistics. Vital Health Stat 13(101). 1989.

20. Cryer C. ICE Injury Indicators Group (ICEIInG)-Progress Report, aspirations, goals and strategy development. In: 

Fingerhut L, ed. Proceedings of the International Collaborative Effort on Injury Statistics Volume IV. Paris: International 

Collaborative Effort on Injury Statistics 3.1–3.12. 2003.

21. Bernstein AB, Hing E, Moss AJ, Allen KF, Siller AB, Tiggle RB. Health care in America: Trends in utilization. Hyattsville, 

Maryland: National Center for Health Statistics. 2003.

22. Weinick RM, Cohen JW. Leveling the playing field: Managed care enrollment and hospital use, 1987–1996. Health Affairs 19(3): 178–98. May/June 2000. 

23. Kuttner R. The American health care system: Employer-sponsored coverage. N Engl J Med 340 (3): 248–52. January 

21, 1999. 

24. Kozak LJ, Hall MJ, Pokras R, Lawrence L. Ambulatory surgery in the United States, 1994. Advance data from vital and 

health statistics; no 283. Hyattsville, Maryland: National Center for Health Statistics. 1997.

25. American Hospital Association. Ambulatory care trendlines: Outpatient surgery trends, 1980–90. 1(2). 1992.

26. Centers for Disease Control and Prevention, Mass Trauma Preparedness and Response http://www.cdc.gov/

masstrauma/default.htm

References
National Trends in Injury Hospitalizations, 1979-2001 10 

Injury and Noninjury Discharges

Injury discharges accounted for 6 percent (1.8 million) of all short-stay hospital discharges in 2001, 

down from 9 percent (3.3 million) in 1979. From 1979 to 2001 the discharge rate for injuries 

decreased on average 4.3 percent per year (for a total decrease of 62 percent) to 64.2 per 10,000 

population. 

Complications of care and adverse effects accounted for 1 percent of all short-stay hospital discharges 

in 1979 and 2 percent in 2001. The discharge rate for complications of care and adverse effects 

increased on average 2.4 percent per year (for a total increase of 68 percent) to 28.2 per 10,000 

population. All other non-injury discharges decreased on average 2.2 percent per year (for a total 

decrease of 39 percent) to 1062.2 per 10,000 population.

Complications of care and adverse effects have come under increased scrutiny since 1999 when 

the Institute of Medicine published its report, To Err Is Human: Building a Safer Health System 

(1). Numerous research projects focusing on complications of care and adverse effects have been 

completed or are currently underway (2–6). Throughout the remainder of this report, the State and 

Territorial Injury Prevention Directors Association (STIPDA) definition of injuries, which excludes 

complications of care and adverse effects, will be used.

References

1. Institute of Medicine. To err is human: Building a safer health 

system. Washington, D.C.: National Academy Press. 1999.

2. Zhan C, Miller M. Excess Length of stay, charges, 

and mortality attributable to medical injuries during 

hospitalization. JAMA 290(14):1868–74. 2003.

3. Thomas EJ, Studdert DM, Burstin HR et al. Incidence and 

types of adverse events and negligent care in Utah and 

Colorado. Medical Care 38(3):261–71. 2000. 

4. Agency for Healthcare Research and Quality. HHS Announces 

$50 Million Investment to Improve Patient Safety. Press 

Release, October 11, 2001, Rockville, Maryland. http://

www.ahrq.gov/news/press/pr2001/patsafpr.htm

5. Carolyn M Clancy, M.D., Testimony on Patient Safety: 

Supporting a Culture of Continuous Quality Improvement 

in Hospitals and Other Health Care Organizations before 

the Senate Permanent Subcommittee on Investigations, 

Committee on Governmental Affairs, June 11, 2003.

6. Gawande AA, Zinner MJ, Studdert DM, Brennan TA. Analysis 

of errors reported by surgeons at three teaching hospitals. 

Surgery 133(6):614–21. 2003.

NOTES: See “Table 1” for the ICD-9-CM codes in each category. See data table for data points graphed and additional notes. Figure 2 data are plotted on the log scale. Discharge rates 

are age adjusted using the 2000 standard population (“Appendix A,” Age adjustment). 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 2. Hospital discharge rates by first-listed diagnosis,

1979-2001

Figure 1. Number of hospital discharges by first-listed

diagnosis, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 11

Data table for figures 1 and 2. Hospital discharges for injury and noninjury diagnoses, 1979-2001

SE is standard error.

NOTES: Discharge rates are age adjusted using the 2000 standard population (“Appendix A,” Age adjustment).

See table 1 for the ICD-9-CM codes in each category.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 12 

In 1979 the injury hospital discharge rate for males was 44 percent higher than the rate for females. 

From 1979 to the early 1990s the rate for males declined faster than the rate for females and by the 

mid-1990s the differences between the genders were no longer statistically significant.

From 1979 to 2001 injury hospital discharge rates for white and black males and females decreased 

on average 4.4 to 6.2 percent per year (for a total decrease of 63–75 percent). Black males had the 

highest injury hospital discharge rate.§

Injury Hospital Discharge Rates by Sex and Race

Reference

1. Kozak LJ. Underreporting of race in the National Hospital 

Discharge Survey. Advance data from vital and health 

statistics; no 265. Hyattsville, Maryland: National Center for 

Health Statistics. 1995.

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes. Discharge rates are age adjusted using the 2000 standard population (“Appendix 

A,” Age adjustment).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 3. Injury hospital discharge rates by sex,

1979-2001

Figure 4. Injury hospital discharge rates by race and

sex, 1979-2001

§The National Hospital Discharge Survey (NHDS) data on race of patient are incomplete largely because a number of hospitals 

providing automated data to NHDS did not include race data for any of their patients (Appendix table 4a). For 1979–2001, coding 

of race averaged 85 percent. A study of the limitations of the NHDS data on race found that race is more often missing for white 

persons. NHDS data on race should be interpreted cautiously when the differences among racial groups are small and/or not 

substantiated by other research (1). 
National Trends in Injury Hospitalizations, 1979-2001 13

Data table for figure 3. Injury hospital discharges by sex, 1979-2001

SE is standard error. 

NOTES: Discharge rates are age adjusted using the 2000 standard population (“Appendix A”, Age adjustment).

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 14 

Data table for figure 4. Injury hospital discharges by race and sex, 1979-2001

SE is standard error.

NOTES: Discharge rates are age adjusted using the 2000 standard population (“Appendix A,” Age adjustment).

Discharges for races other than white or black, or with race not stated, are not included in this table.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 15

Appendix table 4a. Number and percent reporting race 

among injury hospital discharges, 1979-2001 

SE is standard error.

--- Category not applicable

1In 1981 “not stated” values were imputed for approximately 11 percent of total records 

so there are no “race not stated” cases that year.

 

NOTE: The National Hospital Discharge Survey data on race are incomplete largely because a number of hospitals providing automated data to the National Hospital Discharge 

Survey did not include race data for any of their patients. 

 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 16 

From 1979 to 2001 injury hospital discharge rates for all age groups 

under 65 years of age decreased on average from 4.7 to 6.5 percent 

per year (for a total decrease of 66–77 percent) for males and females, 

while the rate for those 65 years and over decreased on average only 

1.1 percent per year for males and 0.6 percent per year for females (for 

a total decrease of 21 and 13 percent, respectively).

Injury hospital discharge rates were generally higher for males than for 

females under 65 years of age; however, females 65 years of age and 

over had higher injury discharge rates than males.

In 1979 the injury hospital discharge rates were higher for males aged 

15–24 years (266.0 per 10,000) and females 65 years of age and over 

(283.8 per 10,000 population) than for others. From 1979 to 2001 the 

injury discharge rates for males 15–24 declined on average 6.5 percent 

per year (for a total decrease of 77 percent) to 70.3 per 10,000 in 2001; 

Injury Hospital Discharge Rates by Sex and Age

meanwhile the rates for females 65 years and over decreased only 0.6 

percent per year (for a total decrease of 13 percent) to 248.0 per 10,000 

population. By 2001 discharge rates for females 65 years and over were 

2 to 10 times the rates for other age-sex groups.

For both males and females, those under 15 years of age generally had 

the lowest rates of injury hospitalization. The injury discharge rates 

for males under 15 years of age were higher than the rates for females 

under 15 years of age from 1979 to 1991, but after that time the rates 

for males and females under 15 years of age were generally similar.

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 5. Injury hospital discharge rates among males by

age, 1979-2001

Figure 6. Injury hospital discharge rates among females 

by age, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 17

Data table for figure 5. Injury hospital discharges among males by age, 1979-2001

SE is standard error.

NOTES: Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 18 

Data table for figure 6. Injury hospital discharges among females by age, 1979-2001

SE is standard error.

NOTES: Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 19

Injury diagnosis categories used in this chartbook are defined by the 

Barell Matrix. The Barell Matrix is a two-dimensional array of ICD-9-

CM injury codes§ defined by body region and nature of the injury (1) 

(Appendix A, Barell Matrix and Appendix B). The columns of the matrix 

are defined by nature-of-injury categories and the rows are the body 

region categories. The 36 most detailed rows of the matrix can be 

collapsed for broader groupings of injuries (from 36 rows to 9 rows to 

5 rows). For instance, injuries to the knee can be collapsed to lower 

extremity injuries and then to all extremity injuries. Thus, an injury may 

be defined by 1 of 12 columns (i.e., nature of injury; e.g., fracture), a row 

(i.e., body region; e.g., extremity injury), a combination of cells (fracture 

of the extremities), or a single cell (hip fracture).

The next to last row of the matrix is a category referred to as “system 

wide” injury. This is not consistent with the other rows or columns in 

the matrix. It could just as easily have been treated as the last column 

of the matrix. System wide injuries affect the entire body; they include 

poisoning, toxic effects, foreign bodies, early complications of trauma, 

other and unspecified effects of external cause, late effects of injury, 

poisoning, toxic effects, and other external causes, and child and adult 

Barell Matrix for Injury Diagnosis Categories

maltreatment. The largest category of these systemic injuries includes 

poisonings and toxic effects.

Injury hospital discharge rates are shown in figures 7 and 8 for two 

periods, 1979–82 and 1998–2001. Because of the level of detail provided 

in the cells of the Barell Matrix, rates were calculated using 4 years of data 

in order to increase the reliability of estimates. If only 1 year of data were 

used fewer cells with reliable data could be presented. 

Examples of how to interpret the cells of the Barell Matrix include: (1) the 

total traumatic brain injury (TBI) hospital discharge rate decreased from 

15.6 per 10,000 population for the period 1979–82 to 5.6 per 10,000 

population for the period 1998–2001; (2) hip fracture hospital discharge 

rates increased from 9.5 per 10,000 population for the period 1979–82 to 

11.7 per 10,000 population for the period 1998–2001. 

Trends for the leading nature of injury categories are presented in figures 

9–13; the body region of the injury categories are presented in figures 

14–18, and an example of the intersection of the dimensions of the Barell 

Matrix (cells) is presented in figure 19. 

Reference

1. Barrell V, Aharonson-Daniel L, Fingerhut LA, MacKenzie EJ, et al. An introduction to the Barell body region by 

nature of injury diagnosis matrix. Injury Prevention 8:91-6. 2002.

 §There were a small number of ICD-9-CM coding changes over the study period and 

they minimally affected the total number of injury discharges (“Appendix A,” ICD-9-CM 

addenda affecting injuries). 
National Trends in Injury Hospitalizations, 1979-2001 20 

Total

1 Fractures Dislocation

Sprains and strains InternalOpen wound AmputationsBlood vessels Contusion/ superficial Crushing Burns NervesUn- specified

142.5 50.9 8.8 19.7 17.3 13.7 1.2 0.2 9.5 0.6 3.9 0.8 2.0

TBI1 5.9 0.7 5.2 --

TBI2 9.6 1.6 8.0

TBI3 * * 15.6 2.4 13.2 --

Other head 1.2 1.2 * * --

Face 7.2 4.4 * -- 2.7 *

Eye 1.7 0.9 0.7 *0.1 *

Neck 0.3 * -- 0.3 -- * *

Head, face, neck, unspecified 1.8 * 1.3 * 0.3 -- 0.3

12.3 4.4 * -- 5.1 * 2.0 * 0.4 * 0.3

27.8 6.8 * -- 13.2 5.1 * 2.0 * 0.4 * 0.3

Cervical SCI 0.3 *0.1 0.2

Thoracic/dorsal SCI 0.1 * *0.1

Lumbar SCI *0.1 * *0.1

Sacrum coccyx SCI * -- *

Spine, back, unspecified SCI 0.1 * *0.1

0.7 0.2 0.5

Cervical VCI 3.9 0.6 *0.1 3.1

Thoracic/dorsal VCI 0.9 0.6 * 0.3

Lumbar VCI 3.0 0.9 * 2.1

0.1 *0.1 * *

Spine, back, unspecified VCI *0.1 *0.1 *

8.0 2.3 0.2 5.5

8.7 2.5 0.2 5.5 0.5

Chest/thorax 5.8 2.9 * * 1.3 0.7 * 0.7 * * --

Abdomen 3.5 2.1 0.8 * 0.5 * *

Pelvis/urogenital 10.1 2.0 * 7.4 0.2 0.2 * *0.1 -- * --

Trunk 0.7 * * *0.1 * *0.1 * 0.4

Back and buttocks 1.8 0.9 0.2 0.6 * *0.1

21.9 5.0 *0.1 8.4 3.6 2.0 * 2.1 * 0.2 * 0.4

Shoulder and upper arm 6.4 4.3 0.9 0.7 0.2 * 0.2 * * *

Forearm and elbow 6.7 5.5 0.2 0.2 0.6 * *0.1 * *

Wrist, hand, and fingers 8.1 2.6 0.3 0.9 2.5 0.9 *0.1 0.3 0.3 0.2

Other and unspecified 1.2 * 0.3 * *0.1 *0.1 * 0.1 0.6 *

22.4 12.5 1.4 1.8 3.6 1.0 *0.1 0.4 0.4 0.4 0.6 0.3

Hip 10.5 9.5 0.3 0.2 0.5 * --

Upper leg and thigh 3.2 2.8 -- -- * 0.2 * *0.1

Knee 9.3 0.9 6.6 1.5 0.3 * *

Lower leg and ankle 10.2 9.2 *0.1 0.7 * *0.1 * *0.1

Foot and toes 2.8 1.3 0.1 *0.1 0.6 0.1 0.1 *0.1 0.2

Other and unspecified 3.7 *0.1 0.8 1.8 * * 0.4 * 0.3 0.4

39.8 24.0 7.1 3.2 2.4 0.2 * 1.6 0.2 0.7 0.4

62.2 36.4 8.5 5.0 6.0 1.2 0.1 2.1 0.5 1.1 0.6 0.6

Other multiple 0.1 * * * *0.1

Unspecified sites 7.6 0.1 * 0.7 * 0.7 * 3.2 * 2.1 * 0.7

7.8 0.2 * 0.7 * 0.7 * 3.2 * 2.1 0.1 0.7

14.1

21.9 0.2 * 0.7 * 0.7 * 3.2 * 2.1 0.1 0.7

Traumatic

brain

injury (TBI)

Vertebral

column

injury (VCI)

Total VCI

Total other head, face, and neck

Other head,

face, and

neck

Total head and neck

Total TBI

Total other and unspecified

System wide and late effects

Spinal cord

injury (SCI)

Lower

Total extremities

Total upper extremity

Upper

Total lower extremity

Other and

unspecified

Total spine and back

Total torso

Torso

Total unclassifiable by site

Total SCI

S

Sacrum coccyx VCI pine and back Head and neck Extremities Torso Unclassifiable by site

Body region Nature of injury

Figure 7. Barell Matrix: Injury hospital discharge rates by nature of injury and body region, 1979-1982

-- Quantity zero * Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability). Empty cells = No diagnosis codes. 1Nature of injury figures do not add to total because total includes system wide and late effects. The column totals are derived by summing the totals for each body region. 

NOTES: Rates per 10,000 civilian residential population. Rates are not age adjusted. Numbers may not add to totals because of rounding. See “Appendix B” for the ICD-9-CM codes in each category. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey. 
National Trends in Injury Hospitalizations, 1979-2001 21

Fractures Dislocation

Sprains and strains InternalOpen wound AmputationsBlood vessels Contusion/ superficial Crushing Burns NervesUn- specified

Traumatic

brain

injury (TBI)

Vertebral

column

injury (VCI)

Other head,

face, and

neck

Spinal cord

injury (SCI)

Lower

Upper

Other and

unspecified

Torso

Spine and back Head and neck Extremities Torso Unclassifiable by site

TBI1

TBI2

TBI3

Other head

Face

Eye

Neck

Head, face, neck, unspecified

Cervical SCI

Thoracic/dorsal SCI

Lumbar SCI

Sacrum coccyx SCI

Spine, back, unspecified SCI

Cervical VCI

Thoracic/dorsal VCI

Lumbar VCI

Spine, back, unspecified VCI

Chest/thorax

Abdomen

Pelvis/urogenital

Trunk

Back and buttocks

Shoulder and upper arm

Forearm and elbow

Wrist, hand, and fingers

Other and unspecified

Hip

Upper leg and thigh

Knee

Lower leg and ankle

Foot and toes

Other and unspecified

Other multiple

Unspecified sites

Total VCI

Total other head, face, and neck

Total head and neck

Total TBI

Total other and unspecified

System wide and late effects

Total extremities

Total upper extremity

Total lower extremity

Total spine and back

Total torso

Total unclassifiable by site

Total SCI

Sacrum coccyx VCI

3.8 1.0 2.8 --

1.6 0.3 1.3

0.2 0.2

5.6 1.5 4.1 --

1.1 0.3 * * 0.8

1.8 1.2 * -- 0.6 0.1

0.3 0.2 0.1 * *

0.2 * -- 0.1 * * *

0.7 *0.0 0.4 * 0.2 * *0.0

4.1 1.2 * -- 1.2 *0.0 0.5 * 0.3 * 0.8

9.7 2.7 * -- 4.1 1.2 *0.0 0.5 * 0.3 * 0.8

0.2 0.1 0.1

0.1 0.1 *

*0.0 *0.0 *

* * *

* * * 0.4 0.2 0.2

0.7 0.5 0.1 0.2

0.7 0.6 * *

1.4 1.1 *0.0 0.2

0.1 0.1 * *

* * *

2.9 2.3 0.1 0.5

3.3 2.5 0.1 0.5 0.2

3.3 1.3 * * 1.4 0.2 *0.0 0.3 * 0.1 --

1.9 1.5 0.2 * 0.1 *0.1 *

2.4 2.0 * 0.2 0.1 0.1 * * * * *

0.3 * * *0.1 -- *0.1 -- 0.2

0.3 * *0.0 0.1 -- 0.1

8.2 3.3 * 0.2 3.0 0.5 0.0 0.6 * 0.3 * 0.2

3.7 2.6 0.1 0.8 0.1 * *0.1 * *0.0 *

2.6 2.3 * * 0.2 * * * 0.1

1.7 0.5 *0.1 * 0.6 0.2 *0.0 *0.0 0.2 *

0.3 * * * 0.1 * * *0.1 0.1 *

8.4 5.5 0.2 0.8 0.9 0.2 0.1 0.1 *0.0 0.4 0.1 *0.0

12.2 11.7 0.1 0.1 0.3 * --

2.2 2.1 -- -- * 0.1 * 0.1

1.1 0.5 0.2 0.3 0.1 * *

6.9 6.5 * 0.2 * 0.1 * 0.1

1.3 0.8 * * 0.2 *0.0 *0.0 * 0.2

1.3 * 0.3 0.6 * *0.1 0.1 * 0.1 0.1

25.0 21.5 0.4 0.9 0.8 0.0 *0.1 0.6 *0.1 0.5 0.1

33.3 27.0 0.6 1.6 1.7 0.3 0.2 0.8 0.1 0.9 0.1 0.1

*0.0 * * * *

1.4 * * 0.1 * *0.1 * 0.3 -- 0.8 * 0.1

1.4 * * 0.1 * *0.1 * 0.3 -- 0.8 * 0.1

8.7

10.1 * * 0.1 * *0.1 * 0.3 -- 0.8 * 0.1

64.7 35.6 0.8 2.4 7.2 3.5 0.3 0.2 2.1 0.1 2.3 0.1 1.3

Total

1

Body region Nature of injury

Figure 8. Barell Matrix: Injury hospital discharge rates by nature of injury and body region, 1998-2001

-- Quantity zero * Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability). Empty cells = No diagnosis codes. 1Nature of injury figures do not add to total because total includes system wide and late effects. The column totals are derived by summing the totals for each body region.

NOTES: Rates per 10,000 civilian residential population. Rates are not age adjusted. Numbers may not add to totals because of rounding. See “Appendix B” for the ICD-9-CM codes in each category. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey. 
National Trends in Injury Hospitalizations, 1979-2001 22 

One dimension of the Barell Matrix is the nature of injury. From 1979 to 2001 fractures, sprains and 

strains, open wounds, internal organ injuries, contusions and superficial injuries, and system wide 

injuries accounted for the vast majority of injury hospital discharges (87–94 percent). Throughout 

this time period, fracture discharge rates were higher than the rates for other leading injury diagnoses 

and declined on average only 2 percent per year (for a total decrease of 36 percent) to a rate of 35.4 

per 10,000 population in 2001. 

From 1979 to 2001 the rate for sprains and strains decreased more than did the rates for other types 

of injuries, an average of 11.1 percent per year (for a total decrease of 92 percent) to a rate of 1.9 per 

10,000 population in 2001. Open wounds and contusion/superficial injury discharge rates, decreased 

on average 7.1 and 8.2 percent per year respectively (for total decreases of 80 and 85 percent), to 

rates of 3.3 and 2.3 per 10,000 population in 2001. System wide and internal organ injury discharge 

rates decreased on average 2.8 and 4.5 percent per year, respectively (for total decreases of 46 and 

64 percent), to 9.0 and 7.3 per 10,000 population in 2001.

Discharges by Injury Diagnosis

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes. Discharge rates are age adjusted using the 2000 standard population (“Appendix 

A,” Age adjustment). System wide injuries include poisoning, toxic effects, foreign bodies, early complications of trauma, other and unspecified effects of external causes, late effects of 

injury, poisoning, toxic effects, and other external causes, and child and adult maltreatment. See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 9. Hospital discharge rates by nature of injury

diagnosis, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 23

Data table for figure 9. Injury hospital discharges by nature of injury diagnosis, 1979-2001

SE is standard error.

NOTES: Discharge rates are age adjusted using the 2000 standard population (“Appendix A”, Age adjustment). These rates exclude all other injuries. See Appendix table 

9a for number of all other injury discharges.

System wide injuries include poisoning, toxic effects, foreign bodies, early complications of trauma, other and unspecified effects of external causes, late effects of injury, 

poisoning, toxic effects, and other external causes, and child and adult maltreatment.

See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 24 

Appendix table 9a. Percent distribution of injury hospital discharges by nature of injury diagnosis, 1979-2001

SE is standard error.

NOTES: System wide injuries include poisoning, toxic effects, foreign bodies, early complications of trauma, other and unspecified effects of external causes, late effects of injury, 

poisoning, toxic effects, and other external causes, and child and adult maltreatment.

See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 25

Appendix table 9b. Internal organ injury hospital discharges among males by age, 1979-2001

SE is standard error.

**Not significant.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 26 

Appendix table 9c. Internal organ injury hospital discharges among females by age, 1979-2001

SE is standard error.

*Figure does not meet standard of reliablility or precision (“Appendix A,” Standards of reliability).

**Not significant.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 27

Appendix table 9d. Percent distribution of system wide injury hospital discharges by 

diagnosis, 1979-2001

 SE is standard error.

NOTES: See “Appendix B” for ICD-9-CM diagnosis codes in each category.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 28 

From 1979 to 2001 fracture hospital discharge rates for all male and female age groups under 65 

years of age declined, with average decreases ranging from 2.2 to 5.6 percent per year (for total 

declines ranging from 39 to 72 percent). Neither the rates for males or females 65 and over changed 

significantly over the 22 years.

For persons 45–64 years of age, the fracture hospital discharge rates were similar for males and 

females. For persons under 45 years of age, males generally had higher discharge rates for fractures 

than females. Females 65 years of age and over had the highest discharge rates for fractures. 

Fractures

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes. See “Appendix B” for the ICD-9-CM diagnosis codes for fractures.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey. 

Figure 10. Fracture hospital discharge rates among males

by age, 1979-2001

Figure 11. Fracture hospital discharge rates among

females by age, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 29

Data table for figure 10. Fracture hospital discharges among males by age, 1979-2001

SE is standard error.

** Not significant.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey. 
National Trends in Injury Hospitalizations, 1979-2001 30

Data table for figure 11. Fracture hospital discharges among females by age, 1979-2001

SE is standard error.

**Not significant.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 32 

Poisoning and toxic effects accounted for 6 percent of all injury hospital discharges in 1979 and 11 

percent in 2001. Poisoning was the largest component of system wide injuries. In 1979 poisonings 

accounted for about one-half of the system wide injury discharges and for 70 percent in 2001. Toxic 

effects accounted for 18 percent of system wide injuries in 1979 and 11 percent in 2001 (Appendix 

table 9d).

From 1979 to 2001 poisoning and toxic effects discharge rates decreased for males and females under 

15 years of age, for males aged 15–24 years, and for males and females 65 years and over.

From 1979 to 2001 the overall hospitalization rates for poisoning and toxic effects for males and 

females were generally similar.

In 2001 over one-half of those hospitalized for poisoning and toxic effects had either poisoning by 

analgesics, antipyretics, and antirheumatics (ICD-9-CM code 965) or poisoning by psychotropic drugs 

(ICD-9-CM code 969).

Poisoning and Toxic Effects

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes. See “Appendix B” for the ICD-9-CM diagnosis codes for poisoning and toxic effects.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 12. Poisoning and toxic effects hospital discharge

rates among males by age, 1979-2001

Figure 13. Poisoning and toxic effects hospital discharge 

rates among females by age, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 33

Data table for figure 12. Poisoning and toxic effects hospital discharges among males by age, 1979-2001

SE is standard error.

*Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

**Not significant.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 34 

Data table for figure 13. Poisoning and toxic effects hospital discharges among females by age, 1979-2001

SE is standard error.

**Not significant.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 35

Appendix table 12a. Poisoning and toxic effects hospital discharges by diagnosis, 1979-2001

SE is standard error.

* Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

NOTES: Poisoning by analgesics, antipyretics, and antirheumatics - ICD-9-CM code 965

Poisoning by psychotropic agents - ICD-9-CM code 969

Poisoning by agents primarily affecting the cardiovascular system - ICD-9-CM code 972

Poisoning by other and unspecified drugs and medicinal substances - ICD-9-CM code 977

Toxic effects of other substances, chiefly nonmedicinal as to source - ICD-9-CM code 989

All other poisoning and toxic effect diagnoses - ICD-9-CM codes 960-964, 966-968, 970-971, 973-976, 978-988

Average annual percent change is from 1979-2001, (“Appendix A,” Test of trend).

Average percent change is for 1979-2001, (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 36 

Another dimension of the Barell Matrix is the body region of the injury. The body region of the injury 

can be categorized at various levels of detail, with the four major body regions being: head and neck, 

spine and back, torso, and extremities.

From 1979 to 2001 injury hospital discharge rates decreased for each of the major body regions. 

Extremity injury rates were higher than the rates for the other body regions and declined on average 

3.4 percent per year (for a total decrease of 53 percent) to 32.8 per 10,000 population in 2001. Rates 

were lower for the other major body region categories, but their relative declines were larger. From 

1979 to 2001 the average annual percent decrease for head and neck, spine and back, and torso 

injury hospital discharge rates ranged from 5.4 to 5.8 percent per year (for total decreases of 71–73 

percent) to 10.0, 3.2, and 7.7 per 10,000 population, respectively in 2001. 

Discharges by Body Region

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes. Discharge rates are age adjusted using the 2000 standard population (“Appendix 

A, Age adjustment”). See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 14. Injury hospital discharge rates by body region

of injury, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 37

Data table for figure 14. Injury hospital discharges by body region of injury, 1979-2001

SE is standard error.

* Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

NOTES: Discharge rates are age adjusted using the 2000 standard population (“Appendix A,” Age adjustment).

 gure 9.

See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 38 

Appendix table 14a. Injury hospital discharges by body region of injury, 1979-2001

SE is standard error.

* Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

NOTES: Numb Appendix table 9a. See 

“Appendix B” for the ICD-9-CM diagnosis codes in each category.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 39

Appendix table 14b. Torso injury hospital discharges among males by age, 1979-2001

SE is standard error.

*Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 40

Appendix table 14c. Torso injury hospital discharges among females by age, 1979-2001

SE is standard error.

* Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 42 

Extremity injuries accounted for 43 to 52 percent of all injury hospital discharges from 1979 to 2001 

(data not shown). For both males and females under 65 years of age, discharge rates for both upper 

and lower extremity injuries declined from 1979 to 2001; the average annual percent decrease 

ranged from 3.7 to 6.9 percent per year (for total declines ranging from 56 to 79 percent). In 

contrast, the rates for males and females 65 years of age and over remained unchanged. For patients 

under 45 years of age, extremity injury discharge rates were higher for males than for females. 

Females 65 years of age and over had the highest discharge rate for extremity injury.

From 1979 to 2001 the percent of extremity injury hospital discharges that were upper extremity 

decreased on average 2.1 percent per year (for a total decline of 38 percent) to 25 percent in 2001. 

The percent that were hip injuries increased 4.2 percent per year (for a total increase of 148 percent) 

to 37 percent in 2001, and lower extremity injuries other than hip injuries decreased on average 1.0 

percent per year (for a total decrease of 20 percent). (Appendix table 16c) 

Extremity Injuries

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes. See “Appendix B” for the ICD-9-CM diagnosis codes for extremity injuries.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 15. Extremity injury hospital discharge rates among

males by age, 1979-2001

Figure 16. Extremity injury hospital discharge rates among

females by age, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 43

Data table for figure 15. Extremity injury hospital discharges among males by age, 1979-2001

SE is standard error.

**Not significant.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 44 

Data table for figure 16. Extremity injury hospital discharges among females by age, 1979-2001

SE is standard error.

**Not significant.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 45

Appendix table 15a. Upper extremity injury hospital discharges among males by age, 1979-2001

SE is standard error.

NOTES: See “Appendix B” for ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 46 

Appendix table 15b. Other lower extremity injury hospital discharges among males by age, 1979-2001

SE is standard error.

NOTES: See “Appendix B” for ICD-9-CM diagnosis codes.

Other lower extremity includes all lower extremity injuries except hip injuries.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 47

Appendix table 16a. Upper extremity injury hospital discharges among females by age, 1979-2001

SE is standard error.

* Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 48 

Appendix table 16b. Other lower extremity injury hospital discharges among females by age, 1979-2001

SE is standard error.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Other lower extremity includes all lower extremity injuries except hip injuries.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 49

Appendix table 16c. Extremity injury hospital discharges by body 

region, 1979-2001

SE is standard error.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National 

Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 50 

Head and neck injuries include a wide range of injuries from traumatic brain injury (TBI) to more 

minor injuries to the head, neck, face, or eye. From 1979 to 2001 head and neck injury hospital 

discharge rates decreased for males and females under 65 years of age an average of 4.0 to 7.6 

percent per year (for total decreases of 60 to 82 percent), while rates for those 65 years and over 

decreased on average 1.2 percent per year for males and 1.1 percent per year for females (for total 

decreases of 23 and 22 percent, respectively).

Generally males under 65 years of age had higher rates of head and neck injury discharges than 

females under 65 years of age. For nearly all years in the study period, rates for males and females 

65 years and over were similar. 

In 2001, among males and females, traumatic brain injuries (TBI) by age accounted for 50–70 percent 

of all head and neck injuries. Hospital discharge rates for TBI were generally higher for males than for 

females among the 15–24 and the 25–44 age groups (Appendix tables 17a and 18a). TBI rates for 

those under 65 years of age declined. TBI discharge rates for those 65 years and over did not change 

significantly over the 22 years.

Head and Neck Injuries

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes. See “Appendix B,” for the ICD-9-CM diagnosis codes for head and neck injuries.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 17. Head and neck injury hospital discharge rates

among males by age, 1979-2001

Figure 18. Head and neck injury hospital discharge rates 

among females by age, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 51

Data table for figure 17. Head and neck injury hospital discharges among males by age, 1979-2001

SE is standard error.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 52 

Data table for figure 18. Head and neck injury hospital discharges among females by age, 1979-2001

SE is standard error.

*Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 53

Appendix table 17a. Traumatic brain injury hospital discharges among males by age, 1979-2001

SE is standard error.

**Not significant.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 54

Appendix table 18a. Traumatic brain injury hospital discharges among females by age, 1979-2001

SE is standard error.

*Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

**Not significant

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 56 

When the dimensions of the Barell Matrix are crossed, the cells provide information on both the 

body region of the injury and the nature of the injury (e.g., hip fractures). Hip fracture discharges 

accounted for 24 percent of extremity fracture hospital discharges in 1979 and 42 percent in 2001 

(data not shown).

When analyzed by age and sex, discharge rates for hip fractures were consistently higher for females 

65 years and over than for males (data not shown). Among females 65 years and over, hip fractures 

accounted for the majority of all extremity fractures (Appendix table 19a). From 1979 to 2001 

females 85 years of age and over had the highest discharge rate for hip fractures, approximately

2 to 3 times the rate among females 75–84 years and 10 times the rate among females 65–74 years 

of age.

From 1979 to 2001, hospital discharge rates for hip fractures among females remained relatively 

unchanged among those 65–74 and 75–84 years of age. However, among those 85 years and over 

the rate increased on average 0.7 percent per year (for a total increase of 16 percent) to 336.5 per 

10,000 population in 2001.

Hip Fractures

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes. ICD-9-CM code for hip fracture is 820.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 19. Hip fracture hospital discharge rates among

females 65 years and over by age, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 57

Data table for figure 19. Hip fracture hospital discharges among females 65 years and over 

by age, 1979-2001

SE is standard error.

**Not significant.

NOTES: Hip fracture - ICD-9-CM code 820.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

Rate per 10,000 civilian resident population. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 58

Appendix table 19a. Extremity fracture hospital discharges among 

females 65 years and over by body region, 1979-2001

SE is standard error.

** Not significant.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National 

Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 60 

The ICD-9 External Cause Matrix is a two-dimensional array describing 

both the mechanism or external cause of the injury (e.g., fall, motor 

vehicle traffic, etc.) and the manner or intent of the injury (e.g., selfinflicted, assault, etc.). (See “Appendix A,” ICD-9-CM External Cause of 

Injury Matrix). While this matrix was originally developed for mortality, it 

has been adapted for use with the ICD-9-CM (1).

In 2001 approximately one third of injury hospitalizations did not have 

an external cause code. Of all injury hospitalizations, 30 percent were 

coded to falls, the leading mechanism of injury coded (figure 20), and, 

in addition, 58 percent of all injuries were coded as unintentional or 

accidents (figure 21).

Fractures accounted for about a million injury hospital discharges. Fortyfive percent of fractures were coded as fall-related, 9 percent as motor 

vehicle traffic-related, 12 percent as another external cause, and 34 

percent had no external cause of injury code (appendix table 20c).

External Cause of Injury

In 2001, 1.2 million patients, or 68 percent of patients hospitalized due 

to injury, had at least one recorded external cause code (appendix table 

20a). This percent was similar for males and females, and for white and 

black persons. In the West over three-quarters had these codes. In the 

Northeast and Midwest external cause codes were recorded for about 

two-thirds of the injury discharges, and over 60 percent of discharges in 

the South contained at least one of these codes. The elderly had a lower 

percentage of injury discharges with an external cause code than those 

15–24, 25–44, and 45–64 years of age (appendix table 20f).

Figure 20. Percent distribution of injury hospital

discharges by mechanism, 2001

Figure 21. Percent distribution of injury hospital

discharges by intent, 2001

NOTES: See “Appendix A,” External cause of injury code. See “Appendix C” for the ICD-9-CM external cause codes in each category.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Reference

1. Recommended framework of E-code groupings for presenting injury mortality and morbidity data.

May 15, 2003. See http://www.cdc.gov/ncipc/whatsnew/matrix2.htm and “Appendix C,” ICD-9-CM External 

Cause of Injury Matrix.
National Trends in Injury Hospitalizations, 1979-2001 61

Figure 22. Percent of injury hospital discharges with an external 

cause of injury code, by nature of injury diagnosis and body region 

of injury, 2001

*Data do not meet standard of reliability.

NOTES: See data table for data points graphed and additional notes. See “Appendix A,” External cause of injury code.

See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

There was considerable variation among the various types of injuries in 

the completion of external cause codes (figure 22). Only 55 percent of 

sprains and strains had an external cause compared with about 88 percent 

of those with poisoning and toxic effects. Other categories with at least 

two-thirds external cause completion were open wounds and dislocations.

External Cause of Injury
National Trends in Injury Hospitalizations, 1979-2001 62 

Data table for figure 20. Injury hospital discharges by 

mechanism, 2001

--- Category not applicable.

SE is standard error.

NOTES: See “Appendix A,” External cause of injury code.

See “Appendix C” for the ICD-9-CM external cause codes in each category. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health 

Statistics, National Hospital Discharge Survey.

Data table for figure 21. Injury hospital discharges by 

intent, 2001

Data table for figure 22. Injury hospital discharges with an 

external cause of injury code, by nature of injury diagnosis and 

body region of injury, 2001

SE is standard error.

* Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

NOTES: See “Appendix A,” External cause of injury code.

See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, 

National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 63

Appendix table 20a. Injury hospital discharges 

with an external cause of injury code, 1979-2001

SE is standard error.

NOTES: See “Appendix A,” External cause of injury code.

There were a small number of ICD-9-CM coding changes over the study 

period and they minimally affected the total number of external cause 

codes (“Appendix A,” ICD-9-CM addenda affecting injuries). 

Average annual percent change is from 1979-2001 (“Appendix A,” Test 

of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

 

SOURCE: Centers for Disease Control and Prevention, National Center 

for Health Statistics, National Hospital Discharge Survey.

Appendix table 20b. System wide injury hospital 

discharges by mechanism and intent, 2001

--- Category not applicable.

SE is standard error.

NOTES: See “Appendix A,” External cause of injury code.

See “Appendix B” for the ICD-9-CM diagnosis codes.

See “Appendix C” for the ICD-9-CM external cause codes in each category. 

System wide injuries include poisoning, toxic effects, foreign bodies, early complications of 

trauma, other and unspecified effects of external causes, late effects of injury, poisoning, 

toxic effects, and other external causes, and child and adult maltreatment. 

 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, 

National Hospital Discharge Survey. 

Appendix table 20c. Fracture hospital 

discharges by mechanism, 2001
National Trends in Injury Hospitalizations, 1979-2001 64

Appendix table 20d. Poisoning and toxic effects hospital 

discharges by intent, 2001

Appendix table 20e. Poisoning and toxic effects hospital 

discharges by mechanism, 2001

--- Category not applicable.

* Figure does not meet standard of reliability or precision. (“Appendix A,” Standards 

of reliability).

SE is standard error.

1First-listed diagnosis.

2Assault, legal intervention, and operations of war.

3External cause.

NOTES: See “Appendix A,” External cause of injury code.

See “Appendix B” for the ICD-9-CM diagnosis codes.

See “Appendix C” for the ICD-9-CM external cause codes in each category.

SOURCE: Centers for Disease Control and Prevention, National Center for Health 

Statistics, National Hospital Discharge Survey.

Appendix table 20f. Injury hospital discharges with 

an external cause of injury code by selected patient 

characteristics, 2001

--- Category not applicable.

SE is standard error.

NOTES: See “Appendix A,” Geographic region.

See “Appendix A,” External cause of injury code.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, 

National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 66 

Most of this report is based on hospitalizations with a first-listed injury diagnosis, but the National 

Hospital Discharge Survey (NHDS) also gathers data on up to six additional diagnoses. For this figure, 

average number of diagnoses was obtained by dividing the total number of diagnoses (all listed) 

by the number of discharges. From 1979 to 2001 the average number of total diagnoses for injury 

discharges doubled from 2.2 diagnoses to 4.5 diagnoses per discharge, as compared with the increase 

from 2.2 to 3.9 diagnoses per noninjury discharge.

Starting in the late 1980’s the average number of total diagnoses for injury discharges was 

consistently higher than the average number of total diagnoses for noninjury discharges. This 

difference is due to increases in injury and noninjury diagnoses as well as to increases in external 

cause codes among injury discharges.

From 1979 to 2001 the average number of injury diagnoses per injury discharge increased on 

average 1.0 percent per year (for a total increase of 24 percent) from 1.5 to 1.8 diagnoses per injury 

discharge. There was also an increase in the average number of noninjury diagnoses (0.6 to 1.7 

diagnoses) and in external cause codes (0.2 to 1.0 diagnoses) for injury discharges. 

Average Number of Diagnoses

NOTES: Data are ploted on the log scale. Average number of diagnoses is age adjusted using the 2000 standard population (“Appendix A,” Age adjustment). See data table for data 

points graphed and additional notes. See “Table 1” for the ICD-9-CM codes in each category. External cause codes for this figure are all codes from E800-E999. Average number of total 

diagnoses among injury discharges include injury diagnoses codes, external cause codes, and noninjury codes.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 23. Average number of diagnoses among injury

hospital discharges, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 67

Data table for figure 23. Average number of diagnoses for injury and noninjury hospital discharges, 1979-2001

SE is standard error.

NOTES: Average number of diagnoses is age adjusted using the 2000 standard population (“Appendix A”, Age adjustment).

Dividing the total number of diagnoses (a maximum of seven are collected on the abstract form) by the number of discharges yields the average number of diagnoses for each patient.

See table 1 for the ICD-9-CM codes in each category.

See “Appendix A,” External cause of injury code.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 68

Appendix table 23a. Total number of diagnoses coded for injury 

hospital discharges, 1979-2001

SE is standard error.

NOTES: Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National 

Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 70 

From 1979 to 2001 the total number of days of hospital care decreased 

for both injury (24.8 to 9.0 million days of care per year) and noninjury 

discharges (239 to 150 million days of care per year) on average 5.2 

and 2.8 percent per year, respectively (for total decreases of 69 and 46 

percent). The total days of care for injury hospitalizations accounted for 

9 percent of the total days of care for all hospitalizations in 1979 and for 

6 percent in 2001.

Days of Care

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional 

notes and “table 1” for the ICD-9-CM codes in each category.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics,

National Hospital Discharge Survey.

Figure 24. Number of days of care for injury and

noninjury hospital discharges, 1979-2001

Data table for figure 24. Number of days of care for 

injury and noninjury hospital discharges, 1979-2001

SE is standard error.

NOTES: See “table 1” for the ICD-9-CM codes in each category.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of 

trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent 

change over time).

SOURCE: Centers for Disease Control and Prevention, National Center for 

Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 71

Appendix table 24a. Number of days of care for injury hospital discharges by nature of injury diagnosis,

1979-2001

SE is standard error.

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

System wide injuries include poisoning, toxic effects, foreign bodies, early complications of trauma, other and unspecified effects of external causes, late effects of injury, 

poisoning, toxic effects, other external causes, and child and adult maltreatment.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey. 
National Trends in Injury Hospitalizations, 1979-2001 72

Appendix table 24b. Number of days of care for injury hospital discharges by body region of injury,

1979-2001

SE is standard error. 

* Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

NOTES: See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

“Other and unspecified” does not include system wide injuries. Those estimates are in appendix table 24a.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 74 

From 1979 to 2001 the average length of stay (ALOS) for patients hospitalized for injury was longer 

for those 65 years and over compared with those under 65 years of age. The ALOS for those 65 years 

and over decreased on average 4.4 percent per year (for a total decline of 63 percent) to 6.1 days in 

2001, and the ALOS for those under 65 decreased on average only 1.9 percent per year (for a total 

decrease of 34 percent) to 4.2 days.

For most years the average length of stay for males and females was similar. From 1979 to 2001 the 

ALOS decreased a total of 38 percent for males and 46 percent for females. 

Average Length of Stay by Age and Sex

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes. In figure 26 average length of stay in days is age adjusted using the 2000 standard population (“Appendix A”, Age adjustment).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 25. Average length of stay in days for injury

hospital discharges by age, 1979-2001

Figure 26. Average length of stay in days for injury

hospital discharges by sex, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 75

Data table for figures 25 and 26. Average length of stay in days for injury hospital 

discharges by age and sex, 1979-2001

SE is standard error.

NOTES: Data by sex is age adjusted using the 2000 standard population (“Appendix A,” Age adjustment)

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 76

Appendix table 25a. Average length of stay in days among 

injury and noninjury hospital discharges, 1979-2001

SE is standard error.

NOTES: Average length of stay in days is age adjusted using the 2000 standard population (“Appendix A,” Average length of stay and Age adjustment).

See table 1 for the ICD-9-CM codes in each category.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over 

time).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 78 

The length of stay for each injury type decreased over the time period. From 1979 to 2001 the length 

of stay for internal organ injuries and open wounds decreased on average 0.7 and 2.3 percent per 

year, respectively (for total decreases of 14 and 40 percent). Fractures decreased on average 3.4 

percent per year (for a total decrease of 54 percent), and system wide injuries decreased on average 

2.4 percent per year (for a total decrease of 42 percent). 

Average Length of Stay by Injury Diagnosis

*Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes. System wide injuries include poisoning, toxic effects, foreign bodies, early 

complications of trauma, other and unspecified effects of external cause, late effects of injury, poisoning, toxic effects, and other external causes, and child and adult maltreatment. 

Average length of stay in days is age adjusted using the 2000 standard population (“Appendix A,” Age adjustment). See “Appendix B” for the ICD-9-CM diagnosis codes in each category. 

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 27. Average length of stay in days for injury

hospital discharges by diagnosis, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 79

Data table for figure 27. Average length of stay in days for injury hospital discharges by diagnosis,

1979-2001

SE is standard error.

* Figure does not meet standard of reliability or precision (“Appendix A,” Standards of reliability).

NOTES: Average length of stay in days is age adjusted using the 2000 standard population (“Appendix A,” Average length of stay and Age adjustment).

System wide injuries include poisoning, toxic effects, foreign bodies, early complications of trauma, other and unspecified effects of external causes, late 

effects of injury, poisoning, toxic effects, and other external causes, and child and adult maltreatment.

See “Appendix B” for the ICD-9-CM diagnosis codes in each category.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 80 

Most patients hospitalized for an injury are discharged home. From 1981 to 2001 the percent of injury 

hospitalizations that were discharged home decreased from 83 percent to 75 percent. Discharges 

to long-term care institutions increased from 3 to 8 percent and discharges to short-term facilities 

increased from 2 to 6 percent. Injury hospitalizations that ended with death increased from 1.0 to 1.7 

percent.

From 1981 to 2001 the proportion discharged home decreased on average 0.8 percent per year (for 

a total decline of 15 percent) while the proportion discharged to a short-term facility increased on 

average 5.9 percent per year (for a total increase of 216 percent) and the proportion discharged to 

a long-term care institution increased on average 4.9 percent per year (for a total increase of 162 

percent).

Discharge Disposition

NOTES: 1981 was the first year the National Hospital Discharge Survey collected discharge disposition data. Percents are plotted on the log scale. See data table for data points graphed 

and additional notes. Percent distributions are age adjusted using the 2000 standard population “Appendix A,” Age adjustment. Discharge disposition is defined in “Appendix A,” Discharge disposition.

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 28. Percent distribution of injury hospital 

discharges by selected discharge disposition, 1981-2001
National Trends in Injury Hospitalizations, 1979-2001 81

Data table for figure 28. Injury hospital discharges by selected discharge disposition, 

1981-2001

SE is standard error.

NOTES: 1981 was the first year the National Hospital Discharge Survey collected discharge disposition data.

All discharge dispositions are not shown in this table, see “Appendix A” for discharge disposition definition.

Percent distributions are age adjusted using the 2000 standard population (“Appendix A,” Age adjustment).

Average annual percent change is from 1981-2001 (“Appendix A,” Test of trend).

Average percent change is for 1981-2001 (“Appendix A,” Average percent change over time).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 82 

From 1981 to 2001 the decline in injury hospitalizations discharged home was greater for those 65 

years and over than for those younger. The decline among those 65 years and over was on average 4 

percent per year (for a total decline of 56 percent) compared with those under 65 years of age with a 

decline on average of 0.5 percent per year (for a total decline of 10 percent).

Discharges to long-term care institutions among those 65 years and over more than doubled from 

1981 to 2001 rising to nearly 40 percent of this age group’s injury hospital discharges. Discharges to 

short-term facilities for this age group increased from 3 percent in 1981 to 11 percent in 2001.

Discharge Disposition by Age

NOTES: 1981 was the first year the National Hospital Discharge Survey collected discharge disposition data. Percents are plotted on the log scale. See data table for data points 

graphed and additional notes. Discharge disposition is defined in “Appendix A.”

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 29. Percent of injury hospitalizations discharged

home by age, 1981-2001

Figure 30. Percent of injury hospitalizations discharged

to a long-term care institution by age, 1981-2001
National Trends in Injury Hospitalizations, 1979-2001 83

Data table for figures 29 and 30. Injury hospital discharges among selected discharge dispositions by age, 1981-2001

SE is standard error.

NOTES: 1981 was the first year the National Hospital Discharge Survey collected discharge disposition data.

All discharge dispositions are not shown in this table, see “Appendix A” for discharge disposition definition.

Average annual percent change is from 1981-2001 (“Appendix A,” Test of trend).

Average percent change is for 1981-2001 (“Appendix A,” Average percent change over time).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 84 

For persons under 65 years of age, private health insurance was the most common expected source of 

payment for injury hospital discharges throughout 1979 to 2001. Private health insurance declined as 

the expected source of payment on average 1.6 percent per year (for a total decrease of 30 percent) 

to 50 percent in 2001. The proportion of injury discharges under 65 with Medicare§, Medicaid, and 

self-pay as the principal expected payment source increased to 6, 16 and 14 percent, respectively 

in 2001. Worker’s compensation declined on average 3.9 percent per year (for a total decline of 58 

percent) to 4 percent in 2001.

The vast majority of injury hospital discharges for those 65 years and over indicated Medicare§ as the 

principal expected payor, 85 percent in 2001 (appendix table 31a).

§ The number of Medicare discharges may be underestimated in recent years because of increased enrollment of Medicare 

patients in health maintenance organizations (HMOs) or other forms of managed care. These plans may be listed on medical records as the principal expected source of payment even though Medicare remains the primary payor.

Expected Source of Payment

Percent

1980 1985 1990 1995 2000

100

10

1

Private health insurance

Worker's compensation

Medicare

Self-pay

Medicaid

NOTES: Data are plotted on the log scale. See data table for data points graphed and additional notes. Expected source of payment is defined in “Appendix A.”

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.

Figure 31. Percent distribution of injury hospital discharges 

among those under 65 years of age by principal expected

source of payment, 1979-2001
National Trends in Injury Hospitalizations, 1979-2001 85

Data table for figure 31. Injury hospital discharges among those under 65 years of age by principal expected source 

of payment, 1979-2001

SE is standard error.

NOTES: See “Appendix A,” Expected source of payment for definitions.

For years 1979-97 private health insurance includes Blue Cross/Blue Shield, and other private insurance.

For years 1998-2001 private health insurance includes Blue Cross/Blue Shield, HMO/PPO, and other private insurance. 

The number and percent of discharges with principal expected sources of payment of “other government,” “other,” “no charge,” or “not stated” are not shown in this table.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge Survey.
National Trends in Injury Hospitalizations, 1979-2001 86

Appendix table 31a. Injury hospital discharges among those 65 years 

of age and over by principal expected source of payment, 1979-2001

SE is standard error.

1The number of Medicare discharges may be underestimated in recent years because of increased enrollment of Medicare patients in health maintenance organizations (HMOs) or other forms of managed care. These plans may be listed 

on medical records as the principal expected source of payment even though Medicare remains the primary payor.

NOTES: See “Appendix A,” Expected source of payment for definitions.

“All other” includes worker’s compensation, Medicaid, self-pay, other government, no charge, other, and not stated.

For years 1979-1997 private health insurance includes Blue Cross/Blue Shield and other private insurance.

For years 1998-2001 private health insurance includes Blue Cross/Blue Shield, HMO/PPO, and other private insurance.

Average annual percent change is from 1979-2001 (“Appendix A,” Test of trend).

Average percent change is for 1979-2001 (“Appendix A,” Average percent change over time).

SOURCE: Centers for Disease Control and Prevention, National Center for Health Statistics, National Hospital Discharge 

Survey.

National Trends in Injury Hospitalizations, 1979-2001 89

Data Source: The National Hospital Discharge Survey

The National Hospital Discharge Survey (NHDS) is a national probability survey designed to collect and 

produce national annual estimates of information on inpatients discharged from non-Federal short-stay 

hospitals in the United States. This survey, which has been conducted annually by the National Center 

for Health Statistics (NCHS) since 1965, covers the 50 States and the District of Columbia. Since 

1988 hospitals with an average length of stay of less than 30 days for all inpatients, general hospitals, 

or children’s general hospitals have been included in the survey. Prior to that time, only hospitals with 

an average length of stay of less than 30 days were included regardless of specialty. Federal, military, 

and Department of Veterans Affairs hospitals, as well as hospital units of institutions (such as prison 

hospitals), and hospitals with fewer than six beds staffed for patient use, are excluded. 

Patient-level data collected include age, sex, race, diagnoses and procedures, length of stay, discharge 

disposition, and expected source of payment. Administrative and hospital data collected include number of hospital beds, type of ownership, and the geographic region of the hospital.

The design of the survey implemented in 1965 continued through 1987; the redesign with a new 

sample of hospitals, fielded in 1988, is currently in place. The sample for the 1965 NHDS was selected 

in 1964 from a frame of short-stay hospitals listed in the National Master Facility Inventory. A twostage stratified sample design was used, with hospitals stratified according to bed size and geographic 

region. Sample hospitals were selected with probabilities ranging from 1 to 40. Within each participating hospital, a systematic random sample was selected from a daily listing sheet of discharges. 

Within-hospital sampling rates for discharges varied inversely with the probability of hospital selection, 

so that the overall probability of selecting a discharge was approximately the same across the sample.

Data collection was conducted by means of manual abstraction of patient information from sampled 

medical records. Sample selection and transcription of information from inpatient medical records to 

NHDS survey forms were performed by either the hospital staff or representatives of NCHS or both. 

In 1985 a new data-collection procedure was introduced. The procedure involved the purchase of 

computer data tapes from commercial abstracting services that contained the NHDS dataset from 

some hospitals in the NHDS sample. Discharges on these computer files were subjected to the NHDS 

sampling specifications, as well as the computer edits and estimation procedures. These two data collection methods, manual and automated, continue to be used in the NHDS.

A redesign of the NHDS was implemented for the 1988 survey (1). Under the redesign hospitals were 

selected using a modified three-stage sampling design. Units selected at the first stage consisted 

of primary sampling units (PSUs), which could be either hospitals or geographic areas like counties or townships. PSUs were used for the National Health Interview Survey (NHIS), also conducted 

by NCHS. Hospitals within PSUs were then selected at the second stage. Strata at this stage were 

defined by geographic region, PSU size, abstracting service status, PSU, and hospital specialty-size 

groups. Within these strata, hospitals were selected with probabilities proportional to their annual 

number of discharges. At the third stage, a sample of discharges was selected by a systematic random sampling technique.

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 90 

The sampling rate was determined by the hospital’s sampling stratum and the type of data collection 

system (manual or automated) used. Discharge records from hospitals submitting data via commercial abstracting services and selected State data systems (approximately 40 percent of sample hospitals) were arrayed by primary diagnoses, patient sex and age group, and date of discharge before 

sampling.

Although the old and new designs remain quite similar, it is still important to take the redesign into 

account when conducting trend analyses. Some of the differences between NHDS statistics based on 

the sample used for the 1965-87 samples, and those based on the sample drawn in 1988, may be due 

to the survey redesign rather than actual changes in hospital utilization. The injury chartbook tracks 

and reports on long-term trends in injury hospitalizations over the entire period from 1979-2001 so 

that the years around the redesign are only analyzed within a larger context. If researchers use NHDS 

data (including the tables in this chartbook) to compare the years immediately before and after the 

redesign, they should seek substantiation of the differences they find from other data sources. They 

should also review the findings from a report comparing estimates from the original and the new design to see the extent to which the redesign made a difference in injury estimates (2).

The NHDS hospital sample is updated every 3 years by continuing the sampling process among hospitals that become eligible for the survey during the intervening years and by deleting hospitals that are 

no longer NHDS-eligible. 

The basic unit of estimation for NHDS is a sampled discharge. The basic estimation procedure involves inflation by the reciprocals of the probabilities of selection. There are adjustments for nonresponding hospitals and discharges, and a post-ratio adjustment to fixed totals is employed.

Since 1979 the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) 

has been used for classifying diagnoses and procedures in the NHDS (3). Beginning in 1986 the ICD9-CM has undergone minor annual modifications. These modifications become effective in October of 

each year and are published in an addendum. Users of the NHDS who wish to conduct trend analyses 

or other multiple year studies should look up the diagnoses and procedures they are studying in the 

addenda to be sure they include data on the correct codes for each of the years studied. ICD-9-CM 

Addenda and a conversion table can be found online at: http://www.cdc.gov/nchs/icd9.htm ; see “Appendix A,” ICD-9-CM addenda affecting injuries. 

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 91

Definitions and Methods

Alphabetical listing of terms and methodologies used in this report:

Age- Patient’s age at the birthday prior to admission to the hospital. 

Age adjustment-Age adjustment, using the direct method, is the application of age-specific rates in 

a population of interest to a standardized age distribution in order to eliminate differences in observed 

rates that result from age differences in population composition. This adjustment is usually done when 

comparing two or more populations at one point in time or one population at two or more points in 

time. Age-adjusted rates are calculated by the direct method as follows: 

where ri = rate in age group i in the population of interest

pi = standard population in age group i

n = total number of age groups over the age range of the age-adjusted rate

Age adjustment by the direct method requires use of a standard age distribution. The standard for 

age-adjusting estimates from NCHS surveys is the year 2000 projected U.S. resident population. The 

standardized age distribution used in this report is listed in Table I, page 13.

For more information on implementing the 2000 population standard for age-adjusting death rates, 

see Anderson RN, Rosenberg HM. Age Standardization of Death Rates: Implementation of the Year 

2000 Standard. National vital statistics reports; vol. 47 no. 3. Hyattsville, Maryland: National Center 

for Health Statistics.1998 (available online at www.cdc.gov/nchs/data/nvsr/nvsr47/nvs47_03.pdf ). 

For more information on the derivation of age adjustment weights for use with NCHS survey data, see 

Klein RJ, Schoenborn CA. Age Adjustment Using the 2000 Projected U.S. Population. Healthy People 

Statistical Notes no. 20. Hyattsville, Maryland: National Center for Health Statistics. 2001 (available 

online at http://www.cdc.gov/nchs/data/statnt/statnt20.pdf). The year 2000 projected U.S. resident 

population is available through the Bureau of the Census home page at www.census.gov/.

P=Σ pi i=1

n

i=1

n

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 92 

Table I. Projected year 2000 U.S. population and proportion distribution by age for

age-adjusting rates (adapted for NHDS data)

Age Population Proportion distribution 

(weights)

Standard million

Total 274,634,000 1.000000 1,000,000

Under 15 years 58,964,000 0.214700 214,700

15-24 years 38,077,000 0.138646 138,646

25-44 years 81,892,000 0.298186 298,186

45-64 years 60,991,000 0.222081 222,081

65 years and over 34,710,000 0.126387 126,387

SOURCE: Anderson RN, Rosenberg HM. Age Standardization of Death Rates: Implementation of the Year 2000 Standard. 

National vital statistics reports; vol 47 no 3. Hyattsville, Maryland: National Center for Health Statistics. 1998.

Age-adjusted percents and means were calculated using rounded values (one decimal place). Ageadjusted rates were calculated using unrounded values. Data that are age adjusted are noted in the 

figure and table notes. The relative standard errors (RSE) for the unadjusted percents, means, and 

rates were applied to the age-adjusted percents, means, and rates.

Average length of stay- Mean length of stay for discharges. It is calculated by dividing the total 

number of days of care, counting the date of admission but not the date of discharge, by the number 

of discharges. See related Days of care.

Average percent change over time, test of trend, and test of significance between two statistics- In this report, trends in injury statistics (expressed here as rates, means, or percents) are 

summarized by two measures of average percent change (rather than by absolute change) as a “total” 

percent change, referred to in the tables as average percent change (e.g., a total decline of 30 percent for the 22 year period 1979-2001) and as an “average annual” percent change (e.g., an average 

increase of 2 percent per year). 

Weighted least squares regression was used to assess trends in annual estimates (4,5) by fitting a 

linear model to the logarithm of annual estimates (5-7). The inverse of the variance of the logarithm 

of the annual estimates was used as the weights in a weighted least squares algorithm to obtain the 

parameter estimate, ß, and corresponding test statistics and standard errors for the linear regression 

model.

From the fitted regression equation, the average annual percent change (7) in the outcome,

(100 (eß -1)), and the total percent change over the 22 year time period, 100 (eß*22 -1), were calculated for this report.

The regression model used in this report makes use of all data points for the calculation of the percent 

change. Another approach that could have been used to calculate change in the rates subtracts the 

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 93

rate (or percent) for the last year from the value for the first year, dividing by the value at the first 

year and multiplied by 100 percent. 

An estimate of the total percent change based only on the first and last data points differs from an 

estimate of total percent change based on all data points; this difference can be large if either the first 

or last data point differs significantly from the trend of the intervening years. 

For each model tested, the standard error of the parameter estimate, ß, was used to determine whether the parameter estimate differed from zero; this determination was used to indicate 

whether or not there was a statistically significant trend in the injury statistic over the time period. 

[See”Appendix A,” Sampling errors] Terms such as “increases” and “decreases” indicate injury trends 

that were statistically significant at the .05 level. The determination of statistical inference is based 

on the two tailed t-test. The Bonferroni technique for multiple comparisons was used to establish the 

critical value for statistically significant differences (0.05 level of significance) for each set of comparisons within each table. Terms relating to differences such as “higher than” indicate that the difference 

is statistically significant. Terms such as “similar” or “no difference” indicate that the difference is not 

statistically significant. Terms such as “generally higher” or “in most instances” refer to tests involving 

multiple comparisons that were significant at least 70% of the time. A lack of comment regarding the 

difference between any two estimates does not mean that the difference was tested and found to be 

not significant.

Barell Matrix - The two-dimensional array of ICD-9-CM injury codes (as of 1998). Codes are 

grouped by body region of the injury and the nature of the injury. This matrix provides a standard 

format for reporting injury data. This injury diagnosis matrix is a product of the participants in the International Collaborative Effort (ICE) on Injury Statistics. For more information about the Barell Matrix 

refer to the Web site page: www.cdc.gov/nchs/about/otheract/ice/barellmatrix.htm (8), “See Appendix 

B,” Barell Matrix.

Days of care - The total number of days a patient spent in the hospital. A stay of less than 1 day 

(patient admission and discharge on the same day) is counted as 1 day. For patients admitted and 

discharged on different days, the number of days of care is computed by counting all the days from 

(and including) the day of admission to (but not including) the day of discharge. See related: Average 

length of stay, Discharge, Hospital, Patient.

Discharge - A completed inpatient hospitalization. A hospitalization may be completed by death or by 

releasing the patient to the customary place of residence, a nursing home, another hospital, or other 

location, or if the patient leaves against medical advice. Persons with multiple discharges during a 

calendar year may be sampled more than once, thus estimates are for discharges, not individual persons. See related Average length of stay, Days of care, Patient.

Discharge Diagnosis - See First-listed diagnosis.

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 94 

Discharge Disposition - The disposition of a patient on termination of hospitalization into one of the 

following categories: 

• Home or routine discharge - patient returned to previous place of residence after discharge from 

the hospital.

• Long-term care institution - patient entered a nursing home including skilled nursing facilities, 

extended care facilities, custodial care facilities, or other long term care placement upon discharge 

from the hospital.

• Short-term facility - patient transferred to another short-term hospital at discharge, including 

short-term maternity hospitals.

• Dead - patient who died during the inpatient stay. 

• Other or not stated - patient who has no discharge disposition listed or other disposition which 

does not fit into the above categories.

Expected source of payment - The principal expected source of payment for the hospitalization. 

Terms used in figure 31, data table 31, and in appendix table 31 are defined below.

• Medicare - The health insurance program for the aged and disabled administered by the Centers 

for Medicare and Medicaid Services (formerly the Health Care Financing Administration).

• Medicaid - A jointly funded Federal-State health insurance program providing medical care to 

those unable to afford it.

• Worker’s compensation - A State or municipal disability insurance or industrial accident insurance.

• Private health insurance- Includes HMO/PPO, Blue Cross/Blue Shield, and other private.

-HMO/PPO - Any health maintenance organization (HMO) or preferred provider organization 

(PPO) sponsored by consumers, communities, physicians, or hospitals.

-Blue Cross/Blue Shield and other private - A private insurance plan not specified as an HMO/

PPO. This includes Blue Cross/Blue Shield plans, medical coverage provided by life insurance 

companies, casualty insurance companies, health insurance companies, and independent plans 

such as employer/union-sponsored plans and/or self-funded plans (partial or total).

• Self-pay - The majority of the costs for the hospitalization were expected to be paid by the patient, spouse, family, or next-of-kin.

• Other government- Other Federal, State, or local government other than worker’s compensation, 

Medicare, and Medicaid not listed separately including casualty insurance paid by the State, Federal 

or State medical research grant.

• No charge- Patients admitted with the understanding that payment would not be expected because the medical services are free, e.g., charity patients or research or teaching patients.

• Other and not stated- Other nonprofit source of payment, e.g., church, Shriner’s, etc., and no 

source of payment indicated. 

External cause of injury code - External cause of injury and poisoning codes are a supplemental component of the ICD-9-CM. Each code begins with an “E” and is followed by a three- or four-digit number 

(e.g., E800.1). External cause codes are intended to be used in addition to a code from the main chapters of the ICD-9-CM (3). External cause codes provide information on the circumstances and causes of 

injuries.

ICD-9-CM codes E800-E999 excluding E849 (place of occurrence code), E869.4 (Accidental poisoning by 

second-hand tobacco smoke), E870-E879 (Misadventures to patients during surgical and medical care), 

E930-E949 (Drugs, medicinal, and biological substances causing adverse effects in therapeutic use), 

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 95

E967 (Perpetrator of child and adult abuse) were used in this report (with the exception of figure 23 which includes all codes from E800-E999). If more than one external cause code is listed for a given record, this report 

used only the first external cause code listed in the diagnostic code fields which met the criteria for this report 

(9,10). See “Appendix C,” ICD-9-CM External Cause of Injury Matrix. 

First-listed diagnosis - The diagnosis established after study to be chiefly responsible for the admission of the 

patient to the hospital is the principal diagnosis. The first-listed diagnosis is the one specified as the principal diagnosis on the face sheet or discharge summary of the medical record. However, if the principal diagnosis is not 

specified, the first one listed on the face sheet or discharge summary of the medical record is used. The number 

of first-listed diagnoses is equivalent to the number of discharges. 

Geographic region - Hospitals are classified by location in one of the four geographic regions of the United 

States that correspond to those used by the U.S. Bureau of the Census. The four geographic regions are as follows:

• Northeast - Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New 

Jersey, and Pennsylvania

• Midwest - Ohio, Indiana, Illinois, Michigan, Wisconsin, Minnesota, Iowa, Missouri, North Dakota, South 

Dakota, Nebraska, and Kansas

• South - Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, 

Georgia, Florida, Kentucky, Tennessee, Alabama, Mississippi, Arkansas, Louisiana, Oklahoma, and Texas

• West - Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada, Washington, Oregon, 

California, Alaska, and Hawaii

Hospital - The NHDS includes hospitals with an average length of stay for all inpatients of less than 30 days 

(short stay) or those whose specialty is general (medical or surgical) or children’s general. Federal hospitals, 

hospital units of institutions, and hospitals with less than six beds staffed for patient use are excluded. 

ICD-9-CM addenda affecting injuries - Assignment of new diagnostic and procedure codes, fourth and 

fifth-digit expansion of codes, as well as code deletions, are contained in addenda developed by the ICD-9-CM 

Coordination and Maintenance Committee and approved by the Director of NCHS and the Administrator of the 

Centers for Medicare and Medicaid Services (formerly Health Care Financing Administration).

Since 1986 the ICD-9-CM has been updated annually with the exception of 1999. (No addendum was released 

in 1999 because of concerns about instituting coding changes before the millennium crossover.) Addenda to the 

ICD-9-CM become effective on October 1, but the new codes included in NHDS data for October 1 to December 

31 of each year are converted back to their previous code assignments so that annual estimates are based on 

consistent coding.

Table II shows the ICD-9-CM addenda for injuries, the date they were introduced, and the code to which the diagnosis or procedure had been assigned. Specific titles and more detailed information about the coding system 

can be found in appropriate volumes of the ICD-9-CM (3).

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 96 

Table II. Changes in injury ICD-9-CM diagnoses codes from the 1986-2000 addenda

Current code(s) assignment Effective October 1 Previous code(s) assignment

864.05 1992 864.09

864.15 1992 864.19

909.5 1994 909.9

922.31-922.33 1996 922.3

925.1-925.2 1993 925

959.0 (code title restated) 1997 959.0

959.01 1997 854.00

959.09 1997 959.0

965.61 1998 965.6

965.69 1998 965.6

989.81-989.84 1995 989.8

989.89 1995 989.8

995.50-995.55 1996 995.5

995.59 1996 995.5

995.60-995.69 1993 995.0

995.7 2000 None

995.80 1996 995.81

995.81 (code title restated) 1996 995.81

995.82-995.85 1996 995.81

E854.8 1995 E858.8

E869.4 1994 E869.8

E880.1 1995 E884.9

E884.3-E884.4 1995 E884.2

E884.5-E884.6 1995 E884.9

E885.1-E885.4, E885.9 2000 E885

E906.5 1995 E906.3

E908.0-E908.4 1995 E908

E908.8-E908.9 1995 E908

E909.0-E909.4 1995 E909

E909.8-E909.9 1995 E909

E920.5 1995 E920.4

E922.4 1997 E917.9

E924.2 1995 E924.0

E928.3 2000 E928.8

E955.6 1997 E955.9

E967.2 1996 E967.0

E967.3 1996 None

E967.4-E967.8 1996 E967.1

E968.7 2000 E968.8

E968.5 1995 E968.8

E968.6 1997 E968.8

E985.6 1997 E985.4

An online version of Table II can be found at: www.cdc.gov/nchs/data/icd9/icdcnv05.pdf

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 97

ICD-9-CM External Cause of Injury Matrix - The two-dimensional array of ICD-9-CM external cause of 

injury codes is grouped by mechanism and intent of injury e.g., fall (mechanism) and unintentional (intent). 

The categories within the matrix are mutually exclusive. This framework was developed by CDC in collaboration with members of the American Public Health Association’s Injury Control and Emergency Health Services 

Section (ICEHS) (10). The International Collaborative Effort (ICE) on Injury Statistics endorsed the matrix 

for international comparisons. More information can be found online at http://www.cdc.gov/ncipc/whatsnew/

matrix2.htm. See related External cause of injury code and “Appendix C”, ICD-9-CM External Cause of Injury 

Matrix. 

Injury discharge - Hospitalizations where the principal diagnosis (first-listed) is an ICD-9-CM diagnosis including 800-909.2, 909.4, 909.9, 910-994.9, 995.5-995.59, 995.80-995.85 (9).

International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) - The United States currently uses ICD-9-CM to code morbidity diagnoses and inpatient procedures. The ICD-9-CM is 

based on and is compatible with the World Health Organization’s International Classification of Diseases, Ninth 

Revision. ICD-9-CM is divided into 17 chapters and 2 supplemental classifications. The chapters are arranged 

primarily by body system. In addition, there are chapters for infectious and parasitic diseases; neoplasms; 

endocrine, metabolic, and nutritional diseases; mental disorders; complications of pregnancy, childbirth and 

puerperium; certain conditions originating in the perinatal period; congenital anomalies; and symptoms, signs 

and ill-defined conditions. The two supplemental classifications are for factors influencing health status and 

contact with health services and classification of external causes of injury and poisoning. More information 

can be found online at www.cdc.gov/nchs/icd9.htm

International Collaborative Effort on Injury Statistics (ICE on Injury Statistics) - An international 

activity sponsored by the Centers for Disease Control and Prevention’s National Center for Health Statistics. 

The ICE on Injury Statistics also receives funding from the National Institutes of Health’s National Institute of 

Child Health and Human Development. The purpose of the ICE on Injury Statistics is to improve international 

comparability and quality of injury data. The ultimate goal is to provide the data needed to better understand 

the causes of injury and the most effective means of prevention. More information can be found online at 

www.cdc.gov/nchs/advice.htm.

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 98 

Length of stay - See Average length of stay.

Logarithmic scale - A scale used to emphasize relative changes in numbers. The choice of a linear or logarithmic 

(log) scale depends on what the analyst/author wants to emphasize about the graph for the audience-the absolute or 

the relative changes in numbers. The absolute change is the arithmetic difference between two values. The relative 

change is the percent difference between two values. 

The linear scale is the scale most frequently used and recognized, and it emphasizes the absolute changes between 

data points over time (11). Figure 1 is an example of data plotted on a linear (both x and y axes) scale. The absolute 

change from 1970 to 2000 for diagnosis A was 50 (from 10 to 60) and for diagnosis B it was 254 (from 150 to 404). 

Logarithmic scales, on the other hand, emphasize the relative or percentage change between data points. Figure 

2 is a semi-log scale graph (x-axis is linear and y-axis is logarithmic) of the same information as in figure 1. Equal 

distances on a log scale represent an equal percentage change. This feature makes a log graph particularly useful 

for showing rates of change in data. Thus, diagnosis A increased 500 percent from 1970 to 2000 while diagnosis B 

increased 169 percent. 

If the important piece of information to be gleaned from these data is the greater percentage change in diagnosis A 

compared with diagnosis B, then the presentation on the log scale (figure 2) makes that very clear. The linear scale 

(figure 1) more clearly emphasizes the greater absolute magnitude of diagnosis B compared with A. In addition, 

trends can be shown on a log scale to enable measures with large differences in magnitude to be shown on the same 

chart. One potential disadvantage to using the log scale is that the absolute magnitude of changes may appear less 

dramatic (12).

Appendix A: Data Sources, Definitions, and Methods

Figure 1. Number of diagnoses A and B

plotted on a linear scale, 1970-2000

0

100

200

300

400

500

1970 1975 1980 1985 1990 1995 2000

Year

Number (linear scale)

1

10

100

1,000

1970 1975 1980 1985 1990 1995 2000

Year

Diagnosis A

Diagnosis B

Number (log scale)

Diagnosis A

Diagnosis B

Figure 2. Number of diagnoses A and B

plotted on a log scale, 1970-2000
National Trends in Injury Hospitalizations, 1979-2001 99

To properly interpret data on a log scale, the following points should be kept in mind: 

1. A sloping straight line indicates a constant rate (not amount) of increase or decrease in the values.

2. A horizontal line indicates no change.

3. The slope of the line indicates the rate of increase or decrease.

4. Parallel lines, regardless of their magnitude, depict similar rates of change (11).

Because this report is designed to emphasize relative rates of change in injury hospitalizations from 1979 to 

2001, we have chosen to present the data using the logarithmic scale. All of the actual data points are given 

in the detailed data and appendix tables.

Measurement errors - As in any survey, results are subject to nonsampling or measurement errors, which 

include errors due to hospital nonresponse, missing abstracts, information incompletely or inaccurately recorded on abstract forms, and processing errors. In general, less than one-half of one percent of the discharge records failed to include the age or sex of the patient. If the hospital record did not state the age or 

sex of the patient, it was imputed by assigning the patient an age or sex consistent with the age or sex of 

other sampled patients with the same first-listed diagnosis code. 

Data on race were missing on average for about 15 percent of all discharges for all years, but this varies 

by year. The percent of race reporting for injury discharges was similar to the percent of race reporting for 

noninjury discharges. Except for one year, no attempt was made to impute for these missing values. In 

1981 “race not stated” values were imputed for approximately 11 percent of the records so there are no “not 

stated” cases for that year. Data by race are provided by the hospital and are not based on patient self-report. Details about the underreporting of race in the NHDS can be found online at:

www.cdc.gov/nchs/data/ad/ad265.pdf.

For data years before 1996, if dates of admission or discharge were missing or invalid, a length of stay was 

imputed by assigning the patient a stay characteristic of the stays of other patients of the same age. 

A new edit program was developed and implemented for the NHDS beginning in 1996. The updated edit program followed the same general specifications as the previous edit program and was designed to make as few 

changes as possible in the data. However, there may be some minor anomalies that would be apparent when 

examining data over time, performing trend analyses, or examining combinations of variables. Particular features of the new edit program that may affect certain variables are:

• An improved imputation procedure for missing age and sex data was developed, which maintains the 

known distribution of these variables, according to categories of the first-listed diagnosis.

• There is no longer a re-ordering of any procedure codes.

• Principal and additional expected sources of payment are no longer re-ordered, with one exception: 

“Self-Pay” is listed as the principal source only if there are no other sources, or the only other source is 

“Not-Stated;” otherwise it must be listed after every other source (except “Not-Stated”).

• An arbitrary month of admission is no longer assigned to records received from abstract services that 

do not provide the exact date of admission and discharge.

Other edit and imputation procedures may have been applied to data received in automated form prior to 

receipt by NCHS.

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 100 

Patient - A patient is a person who is formally admitted to the inpatient service of a hospital for observation, 

care, diagnosis, or treatment. Persons with multiple discharges during the year may be sampled more than 

once, thus estimates are for discharges, not individual persons. See related Average length of stay, Days of 

care, Discharge, Hospital. 

Percent change - See Average percent change over time.

Population estimates - Hospital utilization rates are computed using U.S. Census Bureau population estimates as denominators. 

Estimates of the civilian resident population as of July 1 of each year from 1979 to 2001 are used to calculate 

rates in this report. These are available in the multi-year public use data file for 1979 to 2000, and 2001 population estimates are provided in the 2001 public use data file. Population estimates for 1979 were adjusted 

based on the 1980 census. The estimates for 1980-89 have been adjusted based on the 1990 decennial census. Population estimates for 1990-2000 have been adjusted for underenumeration using the 1990 National 

Population Adjustment Matrix. Population estimates for 2000 are based on the 1990 census because population estimates from the 2000 census were not available when this report was prepared. Population estimates 

for 2001 are based on the 2000 census. Due to these updates and adjustments, it should be noted that rates 

calculated with these estimates may differ slightly from those appearing in published NCHS reports or those 

calculated from population estimates disseminated with the NHDS single-year file documentation.

Rate - A rate is a measure of an event, disease, or condition in relation to a unit of population for a specified 

time. For example: 

 Discharge rate per 10,000 population=(Number of annual discharges / annual population) *10,000 

Relative standard error - The relative standard error (RSE) is a measure of an estimate’s reliability. The 

RSE of an estimate is obtained by dividing the standard error of the estimate (SE(r)) by the estimate itself (r). 

This quantity is expressed as a percent of the estimate and is calculated as follows: RSE = 100 x (SE(r)/r). 

The RSE is used as a guide to the reliability of the estimate (see Standards of reliability). See related Sampling errors.

Sampling errors - Error introduced by chance because only a sample rather than the entire universe is surveyed. 

Before 1988 standard error estimates for NHDS were produced using a computerized routine based on a 

rigorously unbiased estimator of the variance. To obtain standard errors that would be applicable for a wide 

variety of statistics and that could be prepared at a moderate cost, numerous variances were calculated and a 

best-fit formula was derived. This formula, which is based on an empirically determined relationship between 

the size of an estimate, X, and its relative variance, was used to produce generalized variance curves. These 

curves provide approximations to the relative standard errors that are applicable to estimates of discharges, 

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 101

first-or all-listed diagnoses, all-listed procedures, and days of care, either aggregated or disaggregated by 

selected patient or hospital characteristics. For this report, the standard error estimates for 1979-87 were 

generated using this method.

Since 1988, estimates of sampling variability have been calculated with SUDAAN software, which computes 

standard errors by using a first-order Taylor series approximation of the deviation of estimates from their 

expected values. Bieler and Williams published a description of the software and its approach (13). For this 

report the standard errors for 1988-2001 were generated using this software. See related Relative standard 

error.

Standards of reliability - Based on consideration of the complex sample design of the NHDS, the following 

guidelines are recommended for using NHDS estimates and are used throughout this chartbook:

Estimates with relative standard errors (see Relative standard error definition) of more than 30 percent or 

that are based on fewer than 30 records are not presented due to low reliability; only an asterisk (*)

appears in the tables. Estimates based on 30-59 records are preceded by an asterisk to indicate that they 

also have low reliability. Only an asterisk is shown in the tables if the estimate is less than 5,000 because 

these estimates generally have a relative standard error of more than 30 percent or a sample size of less than 

30. Estimates of discharges of less than 9,000 are preceded by an asterisk because they are generally based 

on fewer than 60 records. Days of care estimates derived from the smaller estimates described in this paragraph are also replaced by or preceded by asterisks.

STIPDA or State and Territorial Injury Prevention Directors Association- The national nonprofit 

organization with membership of public health injury professionals that represents all States and territories. 

Its mission is to promote, sustain, and enhance the ability of State and territorial public health departments 

to reduce death and disability associated with injuries. This is accomplished by disseminating information on 

state-of-the-art injury prevention and control policies and strategies (9). More information about STIPDA can 

be found online at: www.stipda.org.

Test of trend - See Average percent change over time, test of trend, and test of significance between two 

statistics. 

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 102

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Health and Human Services, National Center for Health Statistics, Health Care Financing Administration. 1998. 

http://www.cdc.gov/nchs/icd9.htm

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6. Sirken MG, Shimizu BI, French DK, Brock, DB. Manual on standards and procedures for reviewing statistical reports. Rockville, Maryland: National Center for Health Statistics. 1974.

7. Kleinman JC. “Methodological Issues in the Analysis of Vital Statistics” in Kiely, M: Reproductive and perinatal epidemiology, pp 448-68. Boca Raton, Florida: CRC Press. 1991.

8. Barell V, Aharonson-Daniel L, Fingerhut LA, MacKenzie EJ, et al. An introduction to the Barell body region 

by nature of injury diagnosis matrix. Inj Prev 8:91-6. 2002.

9. Injury Surveillance Workgroup. Consensus Recommendations for using hospital discharge data for injury 

surveillance. Marietta, Georgia: State and Territorial Injury Prevention Directors Association. 2003.

10. Centers for Disease Control and Prevention. Recommended framework for presenting injury mortality 

data. MMWR 46(RR14):1-30. 1997. 

11. Page RM, Cole GE, Timmreck TC: Basic epidemiological methods and biostatistics: A practical guidebook. 

Sudbury, Massachusetts: Jones and Bartlett Publishers. 1995.

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13. Bieler GS, Williams RL. Analyzing Survey Data Using SUDAAN Release 7.5. Research Triangle Institute: 

Research Triangle Park, North Carolina. 1997.

Appendix A: Data Sources, Definitions, and Methods
National Trends in Injury Hospitalizations, 1979-2001 104 

Spine and back Head and neck Extremities Torso Unclassifiable

by site

1 Type 1 TBI

Type 2 TBI

Type 3 TBI 37

3

4 Other head

5 Face

6 Eye

7 Neck

Head, face and neck unspecified

39 38

8

9 Cervical SCI

Thoracic/dorsal SCI 10

11 Lumbar SCI

Sacrum coccyx SCI 12

Spine + back unspecified SCI

40

13

14 Cervical VCI

Thoracic/dorsal VCI 15

16 Lumbar VCI

Sacrum coccyx VCI 17

Spine + back unspecified VCI

42 41

18

19 Chest (thorax)

20 Abdomen

21 Pelvis & urogenital

22 Trunk

43 23 Back and buttock

24 Shoulder & upper arm

25 Forearm & elbow

26 Wrist, hand & fingers

44 27 Oher & unspecified

28 Hip

29 Upper leg & thigh

30 Knee

31 Lower leg & ankle

32 Foot & toes

33 Other & unspecified 46 45

34 Other/multiple

35 Unspecified site

Dislocation

830-839

830

839.0-.1

839.21,.31

839.20,.30

839(.41-.42, .51-.52)

839(.40,.49,.50,.59)

839.61,.71

839.69,.79

831

832

833, 834

835

836

837

838

839.8-.9

Sprains

& strains

840-848

848.0-.1

848.2

847.0

847.1

847.2

847.3-.4

848.3-.4

846, 848.5

847.9

840

841

842

/

843

844.0-.3

845.0

845.1

844.8,.9

848.8-.9

Amputations

885-887,

895-897

887.2-.3

887.0-.1

885-886

887.4-.7

897.2-.3

897.0-.1

895-896

897.4-.7

48 47

Traumatic

brain Injury

System

wide Torso

2

Other head,

face and neck Spinal cord (SCI) Vertebral column (VCI) Other &

unspecified Upper Lower

869

863-866, 868

850(.2-.4)

851-854*, 995.55

Internal

850-854,860-869

952, 995.55

850(.0,.1,.5,.9)

860-862

867

952.1

952.8-.9

952.3-.4

952.2

952.0

879(.8-.9)

890-891,894

881.x0-x1

884

881.x2,882, 883

892-893

879.2-.5

877-878

880

879.6-.7

872, 873.2-.7

870-871

876

Open wound

870-884,

890-894

873.0-.1,.8-.9

875, 879.0-.1

874

36 System-wide & late effects

821

827

829

807.0-.4

813

814-817

806.6-.7

806.2-.3

806.0-.1

805.2-.3

809

810-812

819, 828

Fracture

800-829

805.0-.1

806.8-.9

800, 801, 803, 804(.1-.4,.6-.9)

800, 801, 803, 804(.03-.05,.53-.55)

800, 801, 803, 804(.00,.02,.06,.09),

800, 801, 803, 804(.50,.52,.56,.59)

805.6-.7

805.8-.9

800, 801, 803, 804(.01,.51)

807.5-.6

802

805.4-.5

806.4-.5

822

820

825-826

823-824

818

808

Foreign body (930-939), Early complications of trauma (958), Poisoning (960-979), Toxic Effects (980-989), Other and unspecified effects of external cause (990-994), Child and adult maltreatment (995.50-.54,.59, 995.80-.85), Late effects of

injuries, poisonings, toxic effects and other external causes (905-909) excluding 909(.3, .5)

Crush

925-929

Burns

940-949

Nerves

950-951

953-957

Unspecified

959

Blood

vessels

900-904

950.1-.3

941.x6 951 959.01*

941.x1,.x3-.x5,.x7 /

940, 941.x2 950(.0,.9)

925.2 941.x8 953.0, 954.0

900 925.1 941.x0,.x9, 947.0 957.0 959.09

901 926.19 942.x1-x2 953.1

902.0-.4 / 942.x3, 947.3 953.2, 953.5

902(.5, .81-.82) 926(.0, .12) 942.x5, 947.4 953.3

926.8-.9 942.x0, 942.x9 954.1, .8-.9 959.1

926.11 942.x4

927.0 943.x3-.x6 959.2

927.1 943.x1-x2

927.2-.3 944 959.4-.5

903 927.8-.9 943.x0,.x9 953.4, 955 959.3

928.01

928.00 945.x6

928.11 945.x5

928.10,.21 945.x3-.x4

928.3,.20 945.x1-.x2

904.0-.8 928.8,.9 945.x0-.x9 959.6-.7

902.87,.89 947.1-.2 953.8, 956

953.9, 957.1,.8,.9 959.8,.9 946, 947.8,.9

948, 949 929

Contusuion/

superficial

910-924

918, 921

910, 920

922(.0,.1,.33)

922.2

922.4

911, 922.8-.9

922.31-.32

912, 923.0

923.1

914-915, 923.2-.3

913,923.8,.9

924.01

924.00

924.11

924.10,.21

917, 924.3,.20

916, 924.4-.5

902.9, 904.9 919, 924.8,.9

Body region Nature of injury

Appendix B: The Barell injury diagnosis matrix; classification by body region and nature of injury

(based on five digit ICD-9-CM codes)

For purposes of classification, head injuries are labeled as Type 1 TBI if there is recorded evidence of an intracranial injury or a moderate or a prolonged loss of consciousness (LOC), Shaken Infant Syndrome (SIS), or injuries to the optic 

nerve pathways. Type 2 TBI includes injuries with no recorded evidence of intracranial injury, and LOC of less than one hour, or LOC of unknown duration, or unspecified level of consciousness. Type 3 TBI includes patients with no evidence 

of intracranial injury and no LOC.

*NOTES: 959.01 (added to ICD-9-CM in 1997) is not intended to be assigned to TBI cases; however, in the USA it has been assigned incorrectly to a substantial proportion of cases previously coded 854.

The Matrix is available on the internet at www.cdc.gov/nchs/about/otheract/ice/barellmatrix.htm. Empty cells = No diagnosis codes.
National Trends in Injury Hospitalizations, 1979-2001 105

Unintentional Self-inflicted

Manner/Intent

Assault Undetermined Other

1

E920.0-.9

E830.0-.9, E832.0-.9, E910.0-.9

E880.0-E886.9, E888

E890.0-E899, E924.0-.9

E890.0-E899

E924.0-.9

E922.0-.3,.8, .9

E919 (.0-.9)

E810-E819 (.0-.9)

E810-E819 (.0,.1)

E810-E819 (.2,.3)

E810-E819 (.6)

E810-E819 (.7)

E810-E819 (.9)

E800-E807 (.3), E820-E825 (.6),

E826.1,.9, E827-E829(.1)

E800-807(.2), E820-E825(.7),

E826-E829(.0)

E800-E807 (.0,.1,.8,.9), E820-E825

(.0-.5,.8,.9), E826.2-.8, E827-E829

(.2-.9), E831.0-.9, E833.0-E845.9

E900.0-E909, E928.0-.2

E905.0-.6,.9, E906.0-.4,.5,.9

E927

E850.0-E869.9

E916-E917.9

E911-E913.9

E846-E848, E914-E915, E918,

E921.0-.9, E922.4,.5 E923.0-.9,

E925.0-E926.9, E928.3, E929.0-.5

E928.8, E929.8

E887, E928.9, E929.9

E800-E869, E880-E929

E956

E954

E957.0-.9

E958.1,.2,.7

E958.1

E958.2,.7

E955.0-.4

E958.5

E958.6

E958.3

E950.0-E952.9

E953.0-.9

E955.5,.6,.7,.9,

E958.0,.4

E958.8, E959

E958.9

E950-E959

E966

E964

E968.1

E961, E968.0,.3, E979.3

E968.0, E979.3

E961, E968.3

E965.0-.4, E979.4

E968.5

E962.0-.9

E960.0; E968.2

E963

E960.1, E965.5-.9,

E967.0-.9, E968.4,.6, .7,

E979.0-.2, E979.5-.9

E968.8, E969

E968.9

E960-E969, E979

E986

E984

E987.0-.9

E988.1,.2,.7

E988.1

E988.2,.7

E985.0-.4

E988.5

E988.6

E988.3

E980.0-E982.9

E983.0-.9

E985.5,.6,.7, E988.0,.4

E988.8, E989

E988.9

E980-E989

E974

E970

E972

E973, E975

E971, E978, E990-E994, E996,

E997.0-.2

E977, E995, E997.8, E998, E999

E976, E997.9

E970-E978, E990-E999

E870-E879, E930.0-E949.9

E870-E879

E930.0-E949.9

E800-E999

Cut/pierce

Drowning/submersion

Fall

Fire/burn

Fire/flame

Hot object/substance

Firearm

Machinery

Motor vehicle traffic2

Occupant

Motorcyclist

Pedal cyclist

Pedestrian

Unspecified

Pedal cyclist, other

Pedestrian, other

Transport, other

Natural/environmental

Bites and stings

Overexertion

Poisoning

Struck by, against

Suffocation

Other specified and classifiable3

Other specified,

not elsewhere classifiable

Unspecified

All injury

Adverse effects

Medical care

Drugs

All external causes

Mechanism/cause

1Includes legal intervention (E970-E978) and operations of war (E990-E999). 

2Three 4th-digit codes (.4 [occupant of streetcar], .5 [rider of animal], .8 [other specified person]) are not presented separately because of small numbers. However, because they are included in the overall motor vehicle traffic 

category, the sum of these categories can be derived by subtraction.

3ICD-9-CM E849 code should never be first-listed E code and should only appear as an additional code to specify the place of occurrence of the injury incident and has been excluded from the matrix.

NOTES: ICD-9-CM codes were updated as of August 2004. The matrix is avilable onthe internet at www.cdc.gov/ncipc/whatsnew/matrix2.htm. Empty cells = No diagnosis codes.

Appendix C: Recommended framework of E-code groupings for presenting injury morbidity data (August 16, 2004)

Appendix C was corrected July 2005. Codes outlined in yellow box have been shifted down one row from the original print and online versions.