Rates of Hospitalization Related to Traumatic Brain Injury --- Nine States, 2003

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Traumatic brain injury (TBI) is a major cause of morbidity and mortality in the United States. Each year, on average, TBIs are associated with an estimated 1.1 million emergency department visits, 235,000 hospitalizations, and 50,000 deaths in the United States (1). For 2002, the overall rate of TBI-related hospitalization reported by the 12 states in the CDC TBI surveillance system was 79.0 per 100,000 population (2); across these states, however, the rates varied substantially (from 50.6 in Nebraska to 96.9 in Arizona). To update results from the CDC TBI surveillance system, CDC analyzed data from 2003, the most recent year for which data were available. This report summarizes the results of that analysis, which indicated that an estimated 28,819 persons (87.9 per 100,000 population) were hospitalized with a TBI-related diagnosis in the nine states that reported data for 2003. For all age groups combined, rates were higher among males. Age-specific rates were highest among persons aged >75 years. Unintentional motor-vehicle--traffic incidents (MV-T) and unintentional falls were the two leading causes associated with TBI-related hospitalization. The findings underscore the need for states to continue monitoring the occurrence, external causes, and risk factors for TBI and to design and implement more effective injury-prevention programs.

For 2003, nine states* that were funded by CDC to conduct TBI-related surveillance submitted data using the standard CDC TBI surveillance case definition and methods (3). Probable cases of TBI-related hospitalizations were identified from administrative hospital discharge records coded with International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes and from vital statistics mortality data coded with International Classification of Diseases, Tenth Revision (ICD-10) codes in accordance with the CDC TBI surveillance case definition. The administrative data also included external cause-of-injury codes (E-codes), which were used to classify cases into major intent and cause-of-injury categories (4,5).

For 2003, the nine states reported a total of 30,464 probable cases of TBI-related hospitalization. Five of the nine states were awarded additional funding to conduct medical-record reviews for a random sample of the probable cases. In these states, records for 6,456 cases were successfully reviewed, allowing estimation of the predictive value positive (PVP) of the TBI surveillance case definition (estimated at 0.93 overall). Probable TBI case counts were adjusted downward on the basis of estimated PVP (6). U.S. Census Bureau population estimates by state, age, and sex were combined with the surveillance data to calculate age-adjusted annual incidence rates per 100,000 population. All case counts and rates presented in this report are PVP adjusted.

In 2003, an estimated 28,819 persons were hospitalized with a TBI-related diagnosis in the nine reporting states (Table 1). The age-adjusted rate of TBI-related hospitalization was 87.9 per 100,000 population; this rate ranged from 51.8 in Nebraska to 105.0 in Arizona. Overall and in each reporting state, males had a TBI-related hospitalization rate approximately two times as high as females. Overall and in each reporting state, persons aged >75 years had the highest rates of TBI-related hospitalization; these rates ranged from 184.6 in Alaska to 359.7 in Oklahoma (Table 2). Children aged 5--14 years had the lowest rates of TBI-related hospitalization overall and in each state; these rates ranged from 24.4 in Maryland to 69.7 in Alaska.

Overall, unintentional MV-T incidents and unintentional falls were the leading causes of TBI-related hospitalization (32.1 and 29.8 per 100,000 population, respectively) (Table 3). The rate of MV-T--related TBI hospitalization ranged from 17.6 in Nebraska to 37.8 in Arizona; the rate of fall-related TBI hospitalization ranged from 19.8 in South Carolina to 36.7 in Colorado. Assaults were the third leading cause of TBI-related hospitalization (7.1 per 100,000 population). The rate of assault-related TBI hospitalization ranged from 2.9 in Utah to 9.8 in Alaska.

Most patients hospitalized with a TBI-related diagnosis were discharged home with no or unskilled assistance (64.9%) or with home health care (3.7%). Additionally, 9.0% were discharged to a residential facility (e.g., skilled nursing facility), and 7.7% were transferred for inpatient rehabilitation. Approximately 6.8% of these patients died while hospitalized.

Reported by: VG Coronado, MD, KE Thomas, MPH, Div of Injury Response, SR Kegler, PhD, Div of Violence Prevention, National Center for Injury Prevention and Control, CDC.

Editorial Note:

This report confirms that TBI-related hospitalizations were a major public health problem in the nine reporting states during 2003 but that rates varied substantially by age and sex. Most TBI-related hospitalizations were associated with unintentional MV-T incidents and unintentional falls.

The overall TBI-related hospitalization rate described in this report is higher than the estimate reported by CDC for 2002 (87.9 versus 79.0 per 100,000 population, respectively) (2); however, rates for the individual states providing data for both reporting years did not increase as substantially. For 2002, approximately 54% of all TBI-related hospitalization cases reported to the CDC TBI surveillance system were from New York and California, where rates were the third and fourth lowest among the 12 states reporting for that year (74.4 and 75.8, respectively) (2); these states did not report data for 2003. Although the multistate TBI-related hospitalization rates described in this report are consistent with those reported for 2002, formal comparisons have not been made because of the difference in the numbers of reporting states for the 2 years.

The variability in the state-specific TBI-related hospitalization rates for 2003 and the changes in some of these rates from 2002 might be related to differences and changes in admission practices, administrative coding practices, or underlying differences in TBI risk factors in each state (7). The state-specific differences in rates by sex, age group, and external cause suggest a continuing need for the collection of surveillance data at the state level to support interventions focused on populations at high risk.

The findings in this report are subject to at least two limitations. First, the findings are based on administrative billing data that were not designed for public health surveillance purposes (8). Second, estimates of TBI-related hospitalizations by race/ethnicity could not be reliably produced because of the substantial percentage of cases for which this information was not available. In addition, the data in this report underestimate the incidence of TBI because the analysis excludes 1) preadmission deaths that might have been TBI-related, 2) persons treated and discharged from emergency departments, 3) persons who sought care in outpatient clinics and physician offices, and 4) persons who did not seek medical care after an injury.

Information resulting from TBI surveillance is important for increasing public awareness of TBI and guiding prevention measures. To reduce the burden of TBI in the United States, prevention measures should focus on the leading causes (i.e., MV-T incidents, falls, and assaults) and the implementation of evidence-based prevention interventions (9,10).

References

* Alaska, Arizona, Colorado, Maryland, Minnesota, Nebraska, Oklahoma, South Carolina, and Utah.

ICD-9-CM codes, ICD-10 codes, or both were used to identify cases. Cases identified with multiple qualifying codes were counted as single cases. TBI-related hospitalizations were identified using the following ICD-9-CM codes: 800.0--801.9, 803.0--804.9, 850.0--854.1, 950.1--950.3, 959.01, and 995.55. TBI-related hospitalizations that resulted in death and listed only a mortality code were identified using the following ICD-10 codes: S01.0--S01.9, S02.0, S02.1, S02.3, S02.7--S02.9, S04.0, S06.0--S06.9, S07.0, S07.1, S07.8, S07.9, S09.7--S09.9, T01.0, T02.0, T04.0, T06.0, T90.1, T90.2, T90.4, T90.5, T90.8, and T90.9. Although included in the case definition, T01.0, T02.0, T04.0, and T06.0 are considered invalid codes in the United States.

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