Abstract
This cohort study characterizes US trends in traumatic brain injury–related mortality by age, sex, and race and ethnicity.
Traumatic brain injury (TBI) is a leading cause of death and disability in the US.1 Examination of long-term trends in TBI-related mortality is essential to yield insights into vulnerable population subgroups. We sought to characterize nationally representative trends in TBI-related mortality.
Methods
This cohort study analyzed all TBI-related deaths in the US from 1999 through 2020 via the Centers for Disease Control and Prevention’s (CDC’s) Wide-Ranging Online Data for Epidemiologic Research platform.2 Due to the deidentified nature of the data, this research is considered nonhuman research under US regulation (45 CFR §46.102) and was exempt from review and informed consent. This study followed the STROBE reporting guideline.
We used the CDC surveillance definition of TBI-related mortality (injury-related underlying cause of death and TBI-related ICD-10 codes in at least 1 of 20 multiple-cause-of-death fields).3 For each year, we extracted crude mortality rates per 100 000 overall and by sex (male, female), race and ethnicity (American Indian or Alaska Native, Asian or Pacific Islander, Black, Hispanic, White), and age (<25, 25-49, 50-74, ≥75 years). To account for the changes in age structure of the US population over time, mortality rates were age-standardized to the 2010 US census (using the aforementioned age categories) using R, version 4.2.2 (R Foundation for Statistical Computing). The Joinpoint Regression Program, version 5.0.2 (National Cancer Institute), was used to calculate the average annual percent change (AAPC), 95% CIs, and P values for trend.4 Data were analyzed between March 8 and September 20, 2023. A 2-sided P < .05 was considered statistically significant by t distribution if the overall 1999-2020 AAPC comprised 0 joinpoints or z distribution if 1 or more joinpoints.
Results
There were a total of 1 234 305 TBI-related deaths between 1999 and 2020 (26.8% female and 73.2% male; age range, 0 to ≥85 years; 1.2% American Indian or Alaska Native, 2.2% Asian or Pacific Islander, 11.7% Black, 9.3% Hispanic, and 75.7% White). The overall TBI-related age-standardized mortality rate was stable from 1999 through 2020 (Table). Underlying this stability was a gradual, nonsignificant decline in AAPC in 1999-2007 (−0.22; 95% CI, −0.76 to 0.32) and 2007-2010 (−2.68; 95% CI, −7.63 to 2.74), followed by an increase in 2010-2020 (1.22; 95% CI, 0.82-1.63). The TBI-related mortality rates were consistently higher among males vs females but were stable over time within each sex. By race and ethnicity, TBI-related mortality rates declined over time among Asian and Pacific Islander and Hispanic individuals, were stable among Black individuals, and increased among White individuals. Among American Indian and Alaska Native individuals, TBI-related mortality rates decreased in 1999-2018 (AAPC, −1.69; 95% CI, −2.38 to −0.99), although there was a substantial increase in 2018-2020 (31.03; 95% CI, 5.59-62.60). By age, TBI-related mortality rates declined over time among individuals younger than 25 years but increased among individuals 50 years or older, with the greatest increase occurring among individuals 75 years or older (AAPC, 1.97; 95% CI, 1.80-2.15) (Figure).
Table. Age-Standardized Mortality Rates and Average Annual Percent Change (AAPC) for Traumatic Brain Injury–Related Mortality in the US, 1999-2020.
| Age-standardized mortality rate per 100 000 (95% CI) | 1999-2020 AAPC (95% CI)a | P value for trenda | ||
|---|---|---|---|---|
| 1999 | 2020 | |||
| Overall | 18.64 (18.31 to 18.96) | 19.34 (19.05 to 19.63) | 0.14 (−0.60 to 0.88) | .72 |
| Sex | ||||
| Male | 28.90 (28.31 to 29.49) | 30.17 (29.64 to 30.70) | 0.12 (−0.66 to 0.91) | .76 |
| Female | 9.49 (9.18 to 9.81) | 9.31 (9.04 to 9.59) | −0.05 (−0.35 to 0.25) | .73 |
| Race and ethnicity | ||||
| Non-Hispanic American Indian or Alaska Native | 24.19 (20.10 to 28.62) | 30.89 (26.81 to 35.11) | 1.04 (−0.96 to 3.08) | .31 |
| Non-Hispanic Asian or Pacific Islander | 10.42 (9.05 to 11.80) | 8.49 (7.71 to 9.26) | −0.87 (−1.36 to −0.37) | .001 |
| Non-Hispanic Black | 20.40 (19.39 to 21.41) | 21.29 (20.43 to 22.16) | −0.11 (−0.84 to 0.62) | .76 |
| Hispanic | 14.67 (13.66 to 15.67) | 13.04 (12.41 to 13.67) | −0.87 (−1.67 to −0.07) | .03 |
| Non-Hispanic White | 19.03 (18.65 to 19.41) | 20.85 (20.47 to 21.22) | 0.46 (0.22 to 0.70) | <.001 |
| Age, yb | ||||
| <25 | 12.19 (11.97 to 12.41) | 8.66 (8.48 to 8.84) | −1.92 (−2.90 to −0.93) | <.001 |
| 25-49 | 17.33 (17.07 to 17.58) | 17.08 (16.84 to 17.33) | −0.32 (−1.47 to 0.84) | .59 |
| 50-74 | 19.32 (18.97 to 19.68) | 21.81 (21.62 to 22.11) | 0.64 (0.48 to 0.80) | <.001 |
| ≥75 | 61.43 (60.23 to 62.63) | 84.78 (83.60 to 85.97) | 1.97 (1.80 to 2.15) | <.001 |
Models contained the following number of joinpoints (determined using the weighted Bayesian information criterion): overall, 2 joinpoints (2007, 2010); male: 2 joinpoints (2007, 2010); female, 1 joinpoint (2010); non-Hispanic American Indian or Alaska Native, 1 joinpoint (2018); non-Hispanic Asian or Pacific Islander, 1 joinpoint (2009); non-Hispanic Black, 1 joinpoint (2013); Hispanic, 2 joinpoints (2006, 2011); non-Hispanic White, 1 joinpoint (2011); age younger than 25 years, 2 joinpoints (2006, 2010); age 25 to 49 years, 2 joinpoints (2007, 2010); age 50 to 74 years, 1 joinpoint (2011); age 75 years or older, 0 joinpoints.
Crude and age-standardized mortality rate estimates are equivalent when age is stratified using the categories of younger than 25 years, 25 to 49 years, 50 to 74 years, and 75 years or older.
Figure. Traumatic Brain Injury–Related Mortality Rates in the US by Age, 1999-2020.
Crude and age-standardized mortality rate estimates are equivalent when age is stratified using the categories of younger than 25 years, 25 to 49 years, 50 to 74 years, and 75 years or older. Number of model joinpoints (determined using the weighted Bayesian information criterion) and average annual percentage change (AAPC) for each joinpoint segment by age group are as follows: younger than 25 years, 2 joinpoints (2006, 2010) (AAPC: 1999-2006, −1.82 [95% CI, −2.99 to −0.64]; 2006-2010, −8.14 [95% CI, −12.58 to −3.47]; 2010-2020, 0.61 [95% CI, −0.22 to 1.44]); 25-49 years, 2 joinpoints (2007, 2010) (AAPC: 1999-2007, −0.49 [95% CI, −1.35 to 0.37]; 2007-2010, −4.81 [95% CI, −12.39 to 3.42]; 2010-2020, 1.21 [95% CI, 0.56 to 1.86]); 50-74 years, 1 joinpoint (2011) (AAPC: 1999-2011, 0.26 [95% CI, 0.05 to 0.48]; 2011-2020, 1.14 [95% CI, 0.86 to 1.43]); and 75 years or older, 0 joinpoints (AAPC: 1999-2020, 1.97; 95% CI, 1.80 to 2.15).
Discussion
Although the overall TBI-related mortality in the US was stable over the 22-year study period, this trend obscures a gradual increase in TBI-related mortality over the past decade. This finding highlights the importance of evaluating potential nonlinearities in trends over a long period to identify patterns relevant to public health. We identified sociodemographic subgroups with changing patterns of TBI-related mortality; however, our estimates were less precise among smaller subgroups, including American Indian and Alaska Native individuals. The greatest increase in TBI-related mortality was observed among individuals aged 75 years or older. This group also had the highest absolute rates of TBI-related mortality, suggesting that this may be a high-risk group for targeting prevention measures. Approximately 30% to 40% of TBIs occurring among older individuals are attributable to falls,1 which are a leading cause of mortality among this population.5,6 Thus, future research is warranted to evaluate fall prevention measures as a possible strategy to decrease TBI-related mortality among older individuals.
Data Sharing Statement
References
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Associated Data
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Supplementary Materials
Data Sharing Statement