Journal http://jcn.sagepub.com/ of Child Neurology
The Epidemiology of Traumatic Brain Injury in Children and Youths: A Review of Research Since 1990 David J. Thurman J Child Neurol published online 14 August 2014 DOI: 10.1177/0883073814544363 The online version of this article can be found at: http://jcn.sagepub.com/content/early/2014/08/13/0883073814544363
Published by: http://www.sagepublications.com
Additional services and information for Journal of Child Neurology can be found at: Email Alerts: http://jcn.sagepub.com/cgi/alerts Subscriptions: http://jcn.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
>> OnlineFirst Version of Record - Aug 14, 2014 What is This?
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
Topical Review Article
The Epidemiology of Traumatic Brain Injury in Children and Youths: A Review of Research Since 1990
Journal of Child Neurology 1-8 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0883073814544363 jcn.sagepub.com
David J. Thurman, MD, MPH1
Abstract This report reviews recent research on the epidemiology of traumatic brain injuries among children and youth aged 0 to 20 years. Studies representing populations in North America, Europe, Australia, and New Zealand yield these median estimates of the annual incidence of childhood brain injuries: 691 per 100 000 population treated in emergency departments, 74 per 100 000 treated in hospital, and 9 per 100 000 resulting in death. Males have a higher risk of injury than females: 1.4 times higher among those aged less than 10 years and 2.2 times among those older than 10 years. The leading cause of injury among children aged less than 5 years is falls, whereas the leading cause of injury among youths aged 15 years and older is motor vehicle crashes. The prevalence of disability among all persons who have sustained traumatic brain injury in childhood is unknown, but among those who were hospitalized could approximate 20%. Keywords traumatic brain injury, epidemiology, incidence, risk factors, systematic review Received March 10, 2014. Received revised June 09, 2014. Accepted for publication June 19, 2014.
Traumatic brain injuries are a major burden to public health, having a high incidence and potentially severe long-term consequences. Worldwide, each year in excess of 10 million traumatic brain injuries lead to hospitalization or result in death.1 Globally, such injuries account for a substantial proportion of all neurologic disabilities.2 The public health burden of brain injury is disproportionately high in children, especially adolescents. Epidemiologic studies published between 1978 and 1990 established that across all age groups, the incidence of hospitalized and fatal brain injuries consistently peaked among late adolescents.3 These studies also demonstrated that among children and youths, males had a higher risk of injury than females and that the leading causes of among children were related to motor vehicle and bicycle accidents, falls, and sports- or recreation-related impacts. Despite the higher incidence shown among young people, few epidemiologic studies and reviews of traumatic brain injury incidence have focused primarily on this age group. The purpose of this report, therefore, is to examine and summarize published evidence describing the epidemiology of traumatic brain injuries in children and youths. The occurrence of these injuries—and methods of studying them—have changed over time. Accordingly, most of the evidence considered here will be limited to studies completed after 1990. The occurrence of these injuries also varies substantially among different world regions, in general appearing more common
in lower income countries,1,2 although data from these regions are limited. This scope of this review will include only highincome countries.
Definitions Traumatic Brain Injury For the purposes of epidemiologic studies, the US Centers for Disease Control and Prevention (CDC) and the World Health Organization have provided similar case definitions for traumatic brain injury or, more precisely, craniocerebral trauma.4,5 Summarized, their criteria include an occurrence of injury to the head from physical force, to which one or more of the following symptoms or findings is attributable: (a) decreased or altered level of consciousness or amnesia; (b) other neurologic or neuropsychological changes; (c) skull fracture; (d) traumatic intracranial lesions; or (e) death. This definition is broad, thus including occurrences with manifestations ranging from 1
Emory University School of Medicine, Department of Neurology, Decatur, GA, USA
Corresponding Author: David J. Thurman, MD, MPH, Emory University School of Medicine, Department of Neurology, 468 Pensdale Road, Decatur, GA 30030, USA. Email: [email protected]
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
2
Journal of Child Neurology
transient and mild disruptions of cerebral function (mild concussion) to severe pathologies that result in long-term disability or death. The CDC and World Health Organization have translated these conceptual and clinical definitions of traumatic brain injury into operational definitions that may be used by researchers analyzing administrative health data coded according to the World Health Organization International Classification of Diseases (ICD-9 or ICD-10 revisions)6,7 or derivatives such as the US International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM).8 Since first introduced in 1995, the CDC operational definition has been updated periodically. The accuracy of traumatic brain injury case identification from data coded under ICD-9 or ICD-10 is less than the accuracy obtained from reviewing clinical information in original medical records. Using the CDC operational case definition, the sensitivity of ICD-9-coded mortality data appears to be fair (78%),9 but evaluations of coded data from clinical care sites show that hospitals and especially emergency departments yield substantially lower estimates of sensitivity.10,11 A particular problem is the ICD-9-CM code representing ‘‘head injury, unspecified’’ (959.01) that was introduced by the US National Center for Health Statistics in 1998 and subsequently included in the CDC case definition. Since then, this code has become frequently used in medical records, applied both to mild concussions as well as to scalp and other superficial head injuries that involve no brain injury. Using clinical criteria for traumatic brain injury as a reference, it has a low positive predictive value of only 19%.10 Thus, the use of ICD-9-CM code 959.01 in the United States could inflate estimates of the incidence of mild traumatic brain injury treated in emergency departments and not admitted to hospital. Both ICD-10 and the proposed ICD-10-CM include apparently equivalent codes (S09.9 and S09.90, respectively), both defined as ‘‘unspecified injury of head.’’7,12 Compared to ICD-9, the ICD-10 and ICD-10-CM codes for traumatic brain injury have been substantially reorganized. The sensitivity and positive predictive values of these newer codes is unknown and will require future evaluation.
Severity Severity refers to the extent of pathophysiologic or pathologic changes identified during the acute period following injury. Severity may help to predict longer-term outcomes, but an absence of apparent longer-term sequelae should not be regarded as conclusive evidence that no traumatic brain injury occurred. Clinicians and researchers have used various standard scales of traumatic brain injury severity. The Glasgow Coma Scale13 is commonly used. Additional common indicators are the duration of unconsciousness, duration of posttraumatic amnesia, and evidence of intracranial pathology obtained from neuroimaging tests. Epidemiologic studies of traumatic brain injury occurrence usually reduce measures of severity to the broad categories of mild (or minor), moderate, and severe, which may be defined by one or more of these indicators. By
most definitions, a mild injury might be one in which the Glasgow Coma Score at the time of hospital presentation indicated minimal or no impairment of consciousness (ie, a score of 13-15), or one in which the duration of unconsciousness (if any) was less than 1 hour (or by some definitions, less than 30 minutes), without evidence of traumatic intracranial lesions. The Abbreviated Injury Scale14 for injuries to the head region, a measure commonly applied to data from trauma care centers, can be used to approximate these definitions of brain injury severity.
Methods This review focuses on reports of population-based epidemiologic studies of traumatic brain injury occurring in high-income (developed) countries. These include studies of medically attended injuries (presenting at nonhospital health care sites, hospital emergency departments, and hospital inpatient services) as well as fatal injuries recorded in vital statistic registries. Some population-based selfreported survey data are also referenced, as are some representative studies of special populations such as athletes. In September and October of 2013, I conducted a search of reports indexed in the MEDLINE database, applying these criteria: indexed under both medical subject headings of ‘‘brain injuries/epidemiology’’ and ‘‘incidence’’ limited to English-language publications since 1990, human studies, and excluding case reports and clinical trials. The search yielded 420 articles whose titles and abstracts I considered. Among these articles, 90 contained language suggesting they might describe brain injury occurrence in populations, and these were selected for full-text review. Of these, 34 reported original data collected by methods meeting the following additional criteria for inclusion in this review: case definitions of traumatic brain injury were explicit and substantially consistent with CDC and World Health Organization definitions; case ascertainment methods were well described and appeared unbiased, designed to systematically detect most or all occurrences in the population of interest, or if methods involved sampling, the sample was representative of the base population; data collection was completed after 1990; estimates of incidence included age-specific strata within the range of 0 to 20 years. Summary estimates of age-specific incidence were derived from the median values for age-specific ranges of each study. Because reported age ranges varied among studies, the mid-point of each reported range was used to map the estimates of each study to the standard age ranges used in this review, that is, 0 to 4 years, 5 to 9 years, 10 to 14 years, and 15 to 19 years. From these summary age-specific estimates, an overall estimate of incidence among children was calculated, age-adjusted by direct method to the standard US population of 2000. Some studies reported age-specific rates for males and females, but not for the combined population. Where these also reported age-specific numbers by sex, it was still possible to calculate the combined rates, which were then used to calculate overall estimates.
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
Thurman
3
Table 1. Incidence of Medically Attended or Fatal Traumatic Brain Injury in Children and Youths. Study authors
Time period Age rangea No. of age strata Incidenceb
Locality
Injuries attended in hospital emergency departments Jager et al16 Guerrero et al15 Injuries attended in hospital inpatient services CDC 199720 Reid et al26 Langlois et al24 Hawley et al22 Baldo et al18 Schneier et al27 Koskinen et al23 Berry et al19 Colantonio et al21 Asemota et al17 Piatt et al25 Fatal injuries only Adekoya et al28 Coronado et al29 All medically attended and fatal injuriese Leibson et al11 McKinlay et al31 Feigin et al30
United States United States
1992-1994 1995-1996
0-24 0-24
3 2
738 643
4 States, United States Minnesota, United States 14 States, United States N. Staffordshire, United Kingdom Veneto, Italy United States Finland Australia Ontario, Canada United States United States
1990-1993 1993 1997 1992-1998 2000 2000 2001-2005 2000-2006 2006-2007 2005-2009 2009
0-24 0-19 0-19 0-14 0-24 0-17 0-19 0-14 0-24 10-19 0-18
3 4 3 1 3 4 2 3 2 5 4
118c 74c 66d 280 290 70 97 91 33 66 54
1998 2007
0-19 0-19
4 4
9.9 8.2
1987-1999 1977-2002 2010-2011
0-15 0-20 0-14
1 4 2
790 1652 973
United States United States Rochester, MN, United States Christchurch, New Zealand New Zealand
a
Age range in years of data applicable to children and youths. Not included are additional data from adults reported from some studies. Annual rate per 100 000 population. All rates age-adjusted to US 2000 population aged 0 to 19 years, except Hawley et al and Leibson et al. c Includes prehospital fatalities. d Excludes in-hospital fatalities. e Includes cases attended within and outside of hospital or hospital emergency departments. b
Where studies specified incidence rates for extended sequential time periods, data representing the most recent period of study were selected for this review. Finally, some data representing brain injuries treated in emergency departments were not included in summaries of incidence when these data were based on case definitions including ICD-9CM code 959.01.
Table 2. Median Male: Female Traumatic Brain Injury Incidence Rate Ratios. Age range Source of data Hospital emergency department11,16,32,34 Hospital19-21,23-25,27,33,35 Mortality28,29 All sources above
0-9 1.2 1.5 1.3 1.4
10-20 2.2 2.2 2.4 2.2
Findings Incidence Table 1 summarizes the annual incidence rates of traumatic brain injury among children and youths reported from 18 studies. Two studies, both from the United States, analyzed data from injuries attended in hospital emergency departments but not admitted to hospital.15,16 From these sources, the median estimate of annual incidence is 691 injuries per 100 000 population. Eleven studies of populations in North America, Europe, and Australia analyzed data from injuries admitted to hospital.17-27 From these, the median estimate of annual incidence is 74 injuries per 100 000 population. Two studies, both from the United States, analyzed mortality data from vital records.28,29 These analyses yielded a median annual rate of 9 fatal injuries per 100 000 population. Finally, 3 studies, from New Zealand and the United States, assessed data for all medically attended or fatal traumatic brain injuries,11,30,31 including
prehospital fatalities, hospitalizations, emergency department visits, as well as other physician office or clinic visits. These yielded a median annual rate of 973 injuries per 100 000. The figure describes age-specific incidence rates of traumatic brain injury, stratified by type of treatment received or data source. Using the median values of age-specific rates of the 18 studies noted above, children aged less than 5 years have the highest incidence of injuries treated in hospital emergency departments. In contrast, compared to younger children, youths aged 15 years and older have a higher incidence of injuries treated in hospital and a much higher incidence of fatal injury. Fifteen studies reported incidence rates of traumatic brain injury for females and males.11,16,19-21,23-25,27-29,32-35 The median values of male-female rate ratios derived from these studies appear in Table 2, stratified by age group and data source.
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
4
Journal of Child Neurology
Table 3. Median Proportions of Traumatic Brain Injury by Selected Cause. Cause (%) Age range
Motor vehicle or transport
Attended in hospital emergency departments or all medically 0-4 7 5-9 13 10-14 19 15 37 Attended in hospital inpatient services17,20,22,24,37,38,40 0-4 15 5-9 29 10-14 54 15 56 Fatal injuries only28,29 0-4 47 5-9 71 10-14 57 15 54
Falls
Sports or recreation
attended11,15,30-32,34,36,39,42 69 5 53 31 37 26 11 20 59 50 23 12
2 4 8 9
4 2 2 1
Combining reports derived from hospital emergency departments, hospital inpatient services, and mortality records, among younger children aged less than 10 years, the risk of injury in males exceeds that of females by a factor of 1.4, while among older children and youths the risk in males exceeds the risk in females by a larger factor of 2.2. These findings vary little when fatal injuries and injuries attended in emergency departments or hospitals are considered separately.
Cause Eighteen studies reported rates or proportions of traumatic brain injuries in children by cause.11,15,17,19,20,22,24,28–32,34,36-40 Table 3 describes the distribution of median percentages for selected leading causes derived from these studies. The distribution by cause is also stratified by age group and principal source of data. The findings may be summarized as follows. Among children aged less than 5 years, falls account for about two-thirds of injuries attended in emergency departments, a majority of injuries attended in hospital, and few fatalities. In this age group, motor vehicle–related incidents account for comparatively small proportions of injuries attended in emergency departments and hospital, but nearly half of fatalities. Among children aged 5 to 14 years whose injuries are attended in emergency departments, falls remain the leading cause, followed by sports or recreation-related injuries, followed by motor vehicle injuries. For those treated in hospital, the leading causes among 5- to 14-year-old children are falls and motor vehicle injuries, the latter accounting for the majority of injuries in older children. Finally, within this age range, motor vehicle incidents cause the majority of fatal injuries, followed by firearms. Among youths aged 15 years or older, whose injuries are attended in emergency departments, motor vehicle–related incidents are the leading cause of brain injury, followed by
Assault
Firearms
1 2 8 22 9 2 3 10 4 10 28 38
assault, followed closely by sports-related incidents. Among youths treated in hospital, a majority of injuries are attributed to motor vehicles. In this age group, most brain injury deaths are attributable either to motor vehicles or to firearms. One study focused entirely on the causes of hospitalized traumatic brain injuries in infants and very young children aged less than 2 years.37 The leading cause of such injury among infants aged less than 1 year was falls (72%), followed by assaultive or abusive head trauma (22%). The leading causes in 1-year-old children were falls (36%), followed by motorvehicle crashes (9%) and abusive head trauma (5%).
Residence Two studies compared risks of traumatic brain injury between children residing in rural and urban areas. In Minnesota, overall rates of injury resulting in hospitalization or death were only slightly higher among those residing in nonmetropolitan areas compared to those in metropolitan areas.26 However, the ratio of nonmetropolitan to metropolitan resident mortality rates was 2.4, a significant finding of higher risk of death among the former. In Colorado, among children and youths 5 to 24 years of age, combined rates of hospitalization and fatal injury were also significantly higher in rural residents compared to urban residents.41 Across all ages including adults, this effect was attributable in large part to differences in rates of motor vehicle–related injuries.
Severity Most studies did not describe the distribution of traumatic brain injuries by severity or did not describe this distribution separately for children. However, one study of statewide emergency department, hospitalization, and mortality data42 estimated less than 2% of nonfatal head injuries to children seen in emergency departments were in the serious-through-
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
Thurman
5
Table 4. Temporal Trends in Rates of Hospitalization and Death Associated With Traumatic Brain Injury. Study population
Interval
% change
Hospitalizations United States, all ages45 United States, children43 Canada, children44
1980-1995 1991-2005 1991-2005
–51.0 –39.0 –63.8
Mortality United States, all ages45,a United States, children43,a United States, all ages28,29
1980-1995 1991-2005 1998-2007
–17.0 –20.0 –17.2
a
In-hospital mortality only.
severe range (Abbreviated Injury Scale score 3 – 6), compared to 31% of such injuries admitted to hospital.a Another study of statewide data26 found that among head injuries in children admitted to hospital, 14% were serious (Abbreviated Injury Scale score 3), whereas 17% were severe (Abbreviated Injury Scale score 4 – 6).b Thus, the vast majority of nonfatal traumatic brain injuries to children evaluated in emergency departments can be regarded as mild, whereas a substantial proportion—nearly a third—of those hospitalized are serious to severe. Among specific causes of injury, using ‘‘falls and other mechanisms’’ as a point of comparison, firearms were most strongly associated with severe injury (odds ratio 88.5), followed by battering (odds ratio 8.6), all-terrain vehicle (odds ratio 8.0), motor vehicle (odds ratio 2.5), and ‘‘struck by objects or persons’’ (odds ratio 2.2).26
Temporal Trends Several studies from North America provided information on trends over time in the incidence of hospitalized or fatal traumatic brain injuries as summarized in Table 4.28,29,43-45 The studies indicated a marked reduction in brain injury hospitalization rates during the past 3 decades: nearly 50% from 1980 to 1995, with similar relative reductions from 1991 to 2005. Substantial though smaller reductions in the incidence of fatal brain injury were also found.
Discussion If we apply the median incidence rates found in this review to the 2014 US population less than 20 years of age,46 we can estimate that this year in the United States approximately 630 000 children and youths will be treated in emergency departments, 60 000 will be hospitalized, and 7500 will die with traumatic brain injury. However, for the following reasons, the data on which these findings are based provide an incomplete and imprecise indication of the burden of traumatic brain injury in the population of children. The inaccuracies of ICD-coded data, upon which most of these studies depend, have already been noted, adversely affecting both the sensitivity and the positive predictive value of case ascertainment. In addition, these data describe only
brain injuries that are medically attended or fatal, leaving a substantial proportion of brain injuries uncounted. According to a US population-based survey representing children and adults, 25% of respondents who reported a head injury with loss of consciousness in the past year indicated that they did not seek medical attention.39 Among children only, the proportion of unattended injuries was not described. While injuries for which medical care is sought might be regarded as generally more serious, it cannot be assumed that all of the many unattended injuries are necessarily inconsequential. For example, many sports-related concussions may not be medically attended. Furthermore, sports injuries are commonly repeated, increasing their potential for adverse long-term outcomes. A discussion of the risk of concussions and other traumatic brain injuries among children and youths engaging in sports and recreation is beyond the scope of this analysis but has been addressed in other reviews47 and in recent guidelines for their management.48 In addition, these data provide only crude indications of the distribution of these traumatic brain injuries by severity. More important, the sources for this review provide scant information about the long-term outcomes of traumatic brain injury in children, specifically the prevalence of consequent impairment and disability. Population-based follow-up studies of adults who have survived following hospitalization for brain injury provide estimates of long-term disability (defined grossly by reduced independence in basic or instrumental activities of daily living) among nearly 40% of survivors.49,50 One population-based Danish study assessed outcomes for a subset of children aged 10 to 14 years who were admitted to hospital between 1979 to 1981 with diagnoses of concussion, brain contusion, or traumatic intracranial hemorrhage.51 The study found that after approximately 15 years, about 20% of the survivors, now young adults, were receiving disability payments. While the overall prevalence of long-term impairment and disability among persons hospitalized in childhood with brain injury has not been established, a substantial burden may be assumed. The population prevalence of impairment and disability following brain injuries treated in emergency departments is unknown, although presumably far lower. As summarized in Table 3, the studies of mortality included in this review28,29 describe only broad categories of cause of injury. These, as well as most of the studies of brain injury morbidity, do not describe pediatric abusive head trauma as a separate category, a critical cause of injury and death in infants. To address the problem of underascertainment and underrecognition of this cause of injury, in 2012 the CDC published recommended case definitions (including indicative ICD-9-CM and ICD-10 code combinations) to identify these cases for epidemiologic studies and public health surveillance.52 Using these standardized definitions, subsequent analyses of representative health and vital data sets in the United States indicate that among children under 2 years of age, abusive head trauma accounts for 27% of all fatal head injuries53 and 21% of all hospitalized head injuries.54 Estimates of hospitalized abusive head trauma may be conservative, inasmuch as some cases
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
6
Journal of Child Neurology
Figure 1. Median estimates of annual traumatic brain injury incidence by age group and source of case report.
cannot be determined because of missing external-cause-ofinjury codes in nearly 10% of head injury records. Clearly, such trauma among infants merits closer attention in future epidemiologic studies. The findings of decreasing rates of hospitalization and death associated with brain injury require interpretation. The reductions in hospitalization appear to arise primarily from criteria enacted in recent years that disproportionately restrict the admission of less severe injuries,45 which presumably are now managed mainly in emergency departments. In addition, a reduced occurrence of all injuries, including brain injuries, has followed successes in injury prevention, especially with improved motor vehicle safety.55 The reductions in death rates associated with brain injury, which are proportionately less than the reductions in hospitalization rates, can be attributed both to injury prevention and to improved medical treatment.
restraints designed for children are effective.56 Therefore, to promote the proper use of child restraints, advocacy of effective public policies as well as more effective education methods for parents are still needed. Among fatal traumatic brain injuries in the United States, firearms rank close to motor vehicles as the next leading agent of injury among older children and youths, a finding that should not be generalized to other high-income countries whose policies are more restrictive of the availability of firearms. In principle, the advocacy and adoption of effective policies to reduce the availability and prevalence of firearms—especially their availability to children and youth— could prevent many of these injuries, notwithstanding current political barriers to their enactment in the United States. Among the causes of less severe traumatic brain injuries, and among younger children, falls predominate, followed by sports and recreation. The circumstances and direct agents of these injuries are manifold, requiring more varied strategies for prevention, sometimes involving personal protective equipment or close attention to the engineering of playground equipment and surfaces.57 Recent guidelines on the management of concussion in sports address some of these issues, including the prevention of injury recurrences.48 The subject of sports-related concussions in youth is also addressed in depth in a recent report of the Institute of Medicine, including recommendations for improved public health surveillance.58 The large public health burden of traumatic brain injury in children clearly justifies greater investment in research on effective methods for their prevention as well as more effective methods for their acute treatment and rehabilitation. With this, continued surveillance and epidemiologic research is necessary as well, with special attention not only to incidence, risk factors, and more specific causes, but also to the longerterm outcomes of these injuries. Declaration of Conflicting Interests The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author received no financial support for the research, authorship, and/or publication of this article.
Conclusions The incidence of traumatic brain injury in children and youths is high, and substantial numbers of those affected incur severe consequences including death or disability. Accordingly, these injuries merit focused attention from neurologists, other health care professionals, and indeed communities at large, with the goals of advancing their prevention as well as their treatment. Prevention has the potential for even greater benefit than improved treatment. Among more severe injuries, 2 underlying causes stand out as important opportunities for prevention. Motor vehicle collisions are still the most common cause, despite improvements in vehicle design and road safety during the past half century. A high proportion of child passengers killed in motor vehicle crashes are still unrestrained or improperly restrained, despite evidence that passenger
Notes a. These estimates of the proportion of severe injury rely on computer-generated approximations to the Abbreviated Injury Scale for the head region (‘‘ICDMAP’’), based on information from ICD-9-CM coded diagnoses, which include indicators of loss of consciousness as well as cranial and intracranial traumatic lesions. In the Abbreviated Injury Scale system, a score of 3 is characterized as ‘‘serious’’ (or ‘‘severe but not life-threatening’’), whereas scores of 4 to 6 are characterized as ‘‘severe,’’ ‘‘critical,’’ or ‘‘maximum’’ (representing increasing levels of risk of death). It should be noted that the ICD-9-CM-based case definition used in this study included code 959.01 (head injury, unspecified), thus including some superficial head injuries that would not meet the clinical definition of traumatic brain injury.
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
Thurman
7
b. These estimates rely on Abbreviated Injury Scale scoring based on a review of the original medical records of cases.
References 1. Murray CJ, Lopez AD. Global Health Statistics. Geneva: World Health Organization; 1996. 2. World Health Organization. Neurological Disorders: Public Health Challenges. Geneva: World Health Organization; 2006. 3. Kraus JF, Rock A, Hemyari P. Brain injuries among infants, children, adolescents, and young adults. Am J Dis Child. 1990; 144:684-691. 4. Thurman DJ, Kraus JF, Romer CJ, eds. Standards for Surveillance of Neurotrauma. Geneva: World Health Organization; 1996. 5. Thurman DJ, Sniezek JE, Johnson D, Greenspan A, Smith SM. Guidelines for Surveillance of Central Nervous System Injury. Atlanta: Centers for Disease Control and Prevention; 1995. 6. World Health Organization. International Classification of Diseases, 9th Revision. Geneva: World Health Organization; 1977. 7. World Health Organization. International Classification of Diseases, Tenth Revision. Geneva: World Health Organization; 1992. 8. US Department of Health and Human Services. Interntional Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM]. Washington, DC: US Department of Health and Human Services; 1979. 9. Rodriguez SR, Mallonee S, Archer P, Gofton J. Evaluation of death certificate-based surveillance for traumatic brain injury— Oklahoma 2002. Public Health Rep. 2006;121:282-289. 10. Bazarian JJ, Veazie P, Mookerjee S, Lerner EB. Accuracy of mild traumatic brain injury case ascertainment using ICD-9 codes. Acad Emerg Med. 2006;13:31-38. 11. Leibson CL, Brown AW, Ransom JE, et al. Incidence of traumatic brain injury across the full disease spectrum: a population-based medical record review study. Epidemiology. 2011;22:836-844. 12. US Department of Health and Human Services. ICD-10-CM Tabular List of Diseases and Injuries. International Classification of Diseases, Tenth Revision, Clinical Modification. Washington, DC: US Department of Health and Human Services; 2014. 13. Teasdale G, Jennett B. Assessment of coma and impaired consciousness: a practical scale. Lancet. 1974;2:81-84. 14. Gennarelli TA, American Association for Automotive Medicine. Committee on Injury Scaling. The Abbreviated Injury Scale. Des Plaines, IL: American Association for Automotive Medicine; 1985. 15. Guerrero JL, Thurman DJ, Sniezek JE. Emergency department visits associated with traumatic brain injury: United States, 1995-1996. Brain Inj. 2000;14:181-186. 16. Jager TE, Weiss HB, Coben JH, Pepe PE. Traumatic brain injuries evaluated in U.S. emergency departments, 1992-1994. Acad Emerg Med. 2000;7:134-140. 17. Asemota AO, George BP, Bowman SM, Haider AH, Schneider EB. Causes and trends in traumatic brain injury for United States adolescents. J Neurotrauma. 2013;30:67-75. 18. Baldo V, Marcolongo A, Floreani A, et al. Epidemiological aspect of traumatic brain injury in Northeast Italy. Eur J Epidemiol. 2003;18:1059-1063.
19. Berry JG, Jamieson LM, Harrison JE. Head and traumatic brain injuries among Australian children, July 2000-June 2006. Inj Prev. 2010;16:198-202. 20. Centers for Disease Control and Prevention. Traumatic brain injury—Colorado, Missouri, Oklahoma, and Utah, 1990-1993. MMWR Morb Mortal Wkly Rep. 1997;46:8-11. 21. Colantonio A, Saverino C, Zagorski B, et al. Hospitalizations and emergency department visits for TBI in Ontario. Can J Neurol Sci. 2010;37:783-790. 22. Hawley CA, Ward AB, Long J, Owen DW, Magnay AR. Prevalence of traumatic brain injury amongst children admitted to hospital in one health district: a population-based study. Injury. 2003; 34:256-260. 23. Koskinen S, Alaranta H. Traumatic brain injury in Finland 1991-2005: a nationwide register study of hospitalized and fatal TBI. Brain Inj. 2008;22:205-214. 24. Langlois JA, Kegler SR, Butler JA, et al. Traumatic brain injuryrelated hospital discharges. Results from a 14-state surveillance system, 1997. Morb Mortal Wkly Rep Surveill Summ. 2003;52:1-20. 25. Piatt JH Jr, Neff DA. Hospital care of childhood traumatic brain injury in the United States, 1997-2009: a neurosurgical perspective. J Neurosurg Pediatr. 2012;10:257-267. 26. Reid SR, Roesler JS, Gaichas AM, Tsai AK. The epidemiology of pediatric traumatic brain injury in Minnesota. Arch Pediatr Adolesc Med. 2001;155:784-789. 27. Schneier AJ, Shields BJ, Hostetler SG, Xiang H, Smith GA. Incidence of pediatric traumatic brain injury and associated hospital resource utilization in the United States. Pediatrics. 2006;118:483-492. 28. Adekoya N, Thurman DJ, White DD, Webb KW. Surveillance for traumatic brain injury deaths—United States, 1989-1998. Morb Mortal Wkly Rep Surveill Summ. 2002;51:1-14. 29. Coronado VG, Xu L, Basavaraju SV, et al. Surveillance for traumatic brain injury-related deaths—United States, 1997-2007. Morb Mortal Wkly Rep Surveill Summ. 2011;60:1-32. 30. Feigin VL, Theadom A, Barker-Collo S, et al. Incidence of traumatic brain injury in New Zealand: a population-based study. Lancet Neurol. 2013;12:53-64. 31. McKinlay A, Grace RC, Horwood LJ, Fergusson DM, Ridder EM, MacFarlane MR. Prevalence of traumatic brain injury among children, adolescents and young adults: prospective evidence from a birth cohort. Brain Inj. 2008;22:175-181. 32. Dahl E, von Wendt L, Emanuelson I. A prospective, populationbased, follow-up study of mild traumatic brain injury in children. Injury. 2006;37:402-409. 33. Perez K, Novoa AM, Santamarina-Rubio E, et al. Incidence trends of traumatic spinal cord injury and traumatic brain injury in Spain, 2000-2009. Accid Anal Prev. 2012;46:37-44. 34. Pickett W, Ardern C, Brison RJ. A population-based study of potential brain injuries requiring emergency care. CMAJ. 2001; 165:288-292. 35. Tieves KS, Yang H, Layde PM. The epidemiology of traumatic brain injury in Wisconsin, 2001. WMJ. 2005;104:22-25, 54. 36. Bazarian JJ, McClung J, Shah MN, Cheng YT, Flesher W, Kraus J. Mild traumatic brain injury in the United States, 1998–2000. Brain Inj. 2005;19:85-91.
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
8
Journal of Child Neurology
37. Eisele JA, Kegler SR, Trent RB, Coronado VG. Nonfatal traumatic brain injury-related hospitalization in very young children—15 states, 1999. J Head Trauma Rehabil. 2006; 21:537-543. 38. Koepsell TD, Rivara FP, Vavilala MS, et al. Incidence and descriptive epidemiologic features of traumatic brain injury in King County, Washington. Pediatrics. 2011;128:946-954. 39. Sosin DM, Sniezek JE, Thurman DJ. Incidence of mild and moderate brain injury in the United States, 1991. Brain Inj. 1996;10:47-54. 40. Thurman DJ, Jeppson L, Burnett CL, Beaudoin DE, Rheinberger MM, Sniezek JE. Surveillance of traumatic brain injuries in Utah. West J Med. 1996;165:192-196. 41. Gabella B, Hoffman RE, Marine WW, Stallones L. Urban and rural traumatic brain injuries in Colorado. Ann Epidemiol. 1997; 7:207-212. 42. McCarthy ML, Serpi T, Kufera JA, Demeter LA, Paidas C. Factors influencing admission among children with a traumatic brain injury. Acad Emerg Med. 2002;9:684-693. 43. Bowman SM, Bird TM, Aitken ME, Tilford JM. Trends in hospitalizations associated with pediatric traumatic brain injuries. Pediatrics. 2008;122:988-993. 44. Colantonio A, Croxford R, Farooq S, Laporte A, Coyte PC. Trends in hospitalization associated with traumatic brain injury in a publicly insured population, 1992-2002. J Trauma. 2009;66:179-183. 45. Thurman D, Guerrero J. Trends in hospitalization associated with traumatic brain injury. JAMA. 1999;282:954-957. 46. CDC Wonder. Census population information. http://wonder.cdc. gov/population.html. Accessed October 24, 2013. 47. Thurman DJ, Branche CM, Sniezek JE. The epidemiology of sports-related traumatic brain injuries in the United States: recent developments. J Head Trauma Rehabil. 1998;13:1-8. 48. Giza CC, Kutcher JS, Ashwal S, et al. Summary of evidence-based guideline update: evaluation and management of concussion in sports: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2013;80: 2250-2257.
49. Selassie AW, Zaloshnja E, Langlois JA, Miller T, Jones P, Steiner CJ. Incidence of long-term disability following traumatic brain injury hospitalization, United States, 2003. J Head Trauma Rehabil. 2008;23:123-131. 50. Whiteneck G, Brooks CA, Mellick D, Harrison-Felix C, Terrill MS, Noble K. Population-based estimates of outcomes after hospitalization for traumatic brain injury in Colorado. Arch Phys Med Rehabil. 2004;85(4 suppl 2):73-81. 51. Engberg A, Teasdale TW. Traumatic brain injury in children in Denmark: a national 15-year study. Eur J Epidemiol. 1998;14: 165-173. 52. Parks SE, Annest JL, Hill HA, Karch DL. Pediatric Abusive Head Trauma: Recommended Definitions for Public Health Surveillance and Research. Atlanta: Centers for Disease Control and Prevention; 2012. 53. Parks SE, Kegler SR, Annest JL, Mercy JA. Characteristics of fatal abusive head trauma among children in the USA: 2003-2007: an application of the CDC operational case definition to national vital statistics data. Inj Prev. 2012;18:193-199. 54. Parks S, Sugerman D, Xu L, Coronado V. Characteristics of non-fatal abusive head trauma among children in the USA, 2003–2008: application of the CDC operational case definition to national hospital inpatient data. Inj Prev. 2012;18:392-398. 55. Dellinger AM, Sleet DA, Jones BH. Drivers, wheels, and roads: motor vehicle safety in the twentieth century. In: Ward JW, Warren C, eds. Silent Victories: the History and Practice of Public Health in Twentieth-century America. New York: Oxford; 2007:343-362. 56. Barraco RD, Cheng JD, Bromberg WJ, et al. Child passenger safety: an evidence-based review. J Trauma. 2010;69: 1588-1590. 57. Centers for Disease Control and Prevention—National Center for Injury Prevention and Control. National Action Plan for Child Injury Prevention. Atlanta: CDC, NCIPC; 2012. 58. Institute of Medicine and National Research Council. Concussions in Youth: Improving the Science, Changing the Culture. Washington, DC: National Academies Press; 2013.
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
The Epidemiology of Traumatic Brain Injury in Children and Youths: A Review of Research Since 1990 David J. Thurman J Child Neurol published online 14 August 2014 DOI: 10.1177/0883073814544363 The online version of this article can be found at: http://jcn.sagepub.com/content/early/2014/08/13/0883073814544363
Published by: http://www.sagepublications.com
Additional services and information for Journal of Child Neurology can be found at: Email Alerts: http://jcn.sagepub.com/cgi/alerts Subscriptions: http://jcn.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
>> OnlineFirst Version of Record - Aug 14, 2014 What is This?
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
Topical Review Article
The Epidemiology of Traumatic Brain Injury in Children and Youths: A Review of Research Since 1990
Journal of Child Neurology 1-8 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0883073814544363 jcn.sagepub.com
David J. Thurman, MD, MPH1
Abstract This report reviews recent research on the epidemiology of traumatic brain injuries among children and youth aged 0 to 20 years. Studies representing populations in North America, Europe, Australia, and New Zealand yield these median estimates of the annual incidence of childhood brain injuries: 691 per 100 000 population treated in emergency departments, 74 per 100 000 treated in hospital, and 9 per 100 000 resulting in death. Males have a higher risk of injury than females: 1.4 times higher among those aged less than 10 years and 2.2 times among those older than 10 years. The leading cause of injury among children aged less than 5 years is falls, whereas the leading cause of injury among youths aged 15 years and older is motor vehicle crashes. The prevalence of disability among all persons who have sustained traumatic brain injury in childhood is unknown, but among those who were hospitalized could approximate 20%. Keywords traumatic brain injury, epidemiology, incidence, risk factors, systematic review Received March 10, 2014. Received revised June 09, 2014. Accepted for publication June 19, 2014.
Traumatic brain injuries are a major burden to public health, having a high incidence and potentially severe long-term consequences. Worldwide, each year in excess of 10 million traumatic brain injuries lead to hospitalization or result in death.1 Globally, such injuries account for a substantial proportion of all neurologic disabilities.2 The public health burden of brain injury is disproportionately high in children, especially adolescents. Epidemiologic studies published between 1978 and 1990 established that across all age groups, the incidence of hospitalized and fatal brain injuries consistently peaked among late adolescents.3 These studies also demonstrated that among children and youths, males had a higher risk of injury than females and that the leading causes of among children were related to motor vehicle and bicycle accidents, falls, and sports- or recreation-related impacts. Despite the higher incidence shown among young people, few epidemiologic studies and reviews of traumatic brain injury incidence have focused primarily on this age group. The purpose of this report, therefore, is to examine and summarize published evidence describing the epidemiology of traumatic brain injuries in children and youths. The occurrence of these injuries—and methods of studying them—have changed over time. Accordingly, most of the evidence considered here will be limited to studies completed after 1990. The occurrence of these injuries also varies substantially among different world regions, in general appearing more common
in lower income countries,1,2 although data from these regions are limited. This scope of this review will include only highincome countries.
Definitions Traumatic Brain Injury For the purposes of epidemiologic studies, the US Centers for Disease Control and Prevention (CDC) and the World Health Organization have provided similar case definitions for traumatic brain injury or, more precisely, craniocerebral trauma.4,5 Summarized, their criteria include an occurrence of injury to the head from physical force, to which one or more of the following symptoms or findings is attributable: (a) decreased or altered level of consciousness or amnesia; (b) other neurologic or neuropsychological changes; (c) skull fracture; (d) traumatic intracranial lesions; or (e) death. This definition is broad, thus including occurrences with manifestations ranging from 1
Emory University School of Medicine, Department of Neurology, Decatur, GA, USA
Corresponding Author: David J. Thurman, MD, MPH, Emory University School of Medicine, Department of Neurology, 468 Pensdale Road, Decatur, GA 30030, USA. Email: [email protected]
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
2
Journal of Child Neurology
transient and mild disruptions of cerebral function (mild concussion) to severe pathologies that result in long-term disability or death. The CDC and World Health Organization have translated these conceptual and clinical definitions of traumatic brain injury into operational definitions that may be used by researchers analyzing administrative health data coded according to the World Health Organization International Classification of Diseases (ICD-9 or ICD-10 revisions)6,7 or derivatives such as the US International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM).8 Since first introduced in 1995, the CDC operational definition has been updated periodically. The accuracy of traumatic brain injury case identification from data coded under ICD-9 or ICD-10 is less than the accuracy obtained from reviewing clinical information in original medical records. Using the CDC operational case definition, the sensitivity of ICD-9-coded mortality data appears to be fair (78%),9 but evaluations of coded data from clinical care sites show that hospitals and especially emergency departments yield substantially lower estimates of sensitivity.10,11 A particular problem is the ICD-9-CM code representing ‘‘head injury, unspecified’’ (959.01) that was introduced by the US National Center for Health Statistics in 1998 and subsequently included in the CDC case definition. Since then, this code has become frequently used in medical records, applied both to mild concussions as well as to scalp and other superficial head injuries that involve no brain injury. Using clinical criteria for traumatic brain injury as a reference, it has a low positive predictive value of only 19%.10 Thus, the use of ICD-9-CM code 959.01 in the United States could inflate estimates of the incidence of mild traumatic brain injury treated in emergency departments and not admitted to hospital. Both ICD-10 and the proposed ICD-10-CM include apparently equivalent codes (S09.9 and S09.90, respectively), both defined as ‘‘unspecified injury of head.’’7,12 Compared to ICD-9, the ICD-10 and ICD-10-CM codes for traumatic brain injury have been substantially reorganized. The sensitivity and positive predictive values of these newer codes is unknown and will require future evaluation.
Severity Severity refers to the extent of pathophysiologic or pathologic changes identified during the acute period following injury. Severity may help to predict longer-term outcomes, but an absence of apparent longer-term sequelae should not be regarded as conclusive evidence that no traumatic brain injury occurred. Clinicians and researchers have used various standard scales of traumatic brain injury severity. The Glasgow Coma Scale13 is commonly used. Additional common indicators are the duration of unconsciousness, duration of posttraumatic amnesia, and evidence of intracranial pathology obtained from neuroimaging tests. Epidemiologic studies of traumatic brain injury occurrence usually reduce measures of severity to the broad categories of mild (or minor), moderate, and severe, which may be defined by one or more of these indicators. By
most definitions, a mild injury might be one in which the Glasgow Coma Score at the time of hospital presentation indicated minimal or no impairment of consciousness (ie, a score of 13-15), or one in which the duration of unconsciousness (if any) was less than 1 hour (or by some definitions, less than 30 minutes), without evidence of traumatic intracranial lesions. The Abbreviated Injury Scale14 for injuries to the head region, a measure commonly applied to data from trauma care centers, can be used to approximate these definitions of brain injury severity.
Methods This review focuses on reports of population-based epidemiologic studies of traumatic brain injury occurring in high-income (developed) countries. These include studies of medically attended injuries (presenting at nonhospital health care sites, hospital emergency departments, and hospital inpatient services) as well as fatal injuries recorded in vital statistic registries. Some population-based selfreported survey data are also referenced, as are some representative studies of special populations such as athletes. In September and October of 2013, I conducted a search of reports indexed in the MEDLINE database, applying these criteria: indexed under both medical subject headings of ‘‘brain injuries/epidemiology’’ and ‘‘incidence’’ limited to English-language publications since 1990, human studies, and excluding case reports and clinical trials. The search yielded 420 articles whose titles and abstracts I considered. Among these articles, 90 contained language suggesting they might describe brain injury occurrence in populations, and these were selected for full-text review. Of these, 34 reported original data collected by methods meeting the following additional criteria for inclusion in this review: case definitions of traumatic brain injury were explicit and substantially consistent with CDC and World Health Organization definitions; case ascertainment methods were well described and appeared unbiased, designed to systematically detect most or all occurrences in the population of interest, or if methods involved sampling, the sample was representative of the base population; data collection was completed after 1990; estimates of incidence included age-specific strata within the range of 0 to 20 years. Summary estimates of age-specific incidence were derived from the median values for age-specific ranges of each study. Because reported age ranges varied among studies, the mid-point of each reported range was used to map the estimates of each study to the standard age ranges used in this review, that is, 0 to 4 years, 5 to 9 years, 10 to 14 years, and 15 to 19 years. From these summary age-specific estimates, an overall estimate of incidence among children was calculated, age-adjusted by direct method to the standard US population of 2000. Some studies reported age-specific rates for males and females, but not for the combined population. Where these also reported age-specific numbers by sex, it was still possible to calculate the combined rates, which were then used to calculate overall estimates.
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
Thurman
3
Table 1. Incidence of Medically Attended or Fatal Traumatic Brain Injury in Children and Youths. Study authors
Time period Age rangea No. of age strata Incidenceb
Locality
Injuries attended in hospital emergency departments Jager et al16 Guerrero et al15 Injuries attended in hospital inpatient services CDC 199720 Reid et al26 Langlois et al24 Hawley et al22 Baldo et al18 Schneier et al27 Koskinen et al23 Berry et al19 Colantonio et al21 Asemota et al17 Piatt et al25 Fatal injuries only Adekoya et al28 Coronado et al29 All medically attended and fatal injuriese Leibson et al11 McKinlay et al31 Feigin et al30
United States United States
1992-1994 1995-1996
0-24 0-24
3 2
738 643
4 States, United States Minnesota, United States 14 States, United States N. Staffordshire, United Kingdom Veneto, Italy United States Finland Australia Ontario, Canada United States United States
1990-1993 1993 1997 1992-1998 2000 2000 2001-2005 2000-2006 2006-2007 2005-2009 2009
0-24 0-19 0-19 0-14 0-24 0-17 0-19 0-14 0-24 10-19 0-18
3 4 3 1 3 4 2 3 2 5 4
118c 74c 66d 280 290 70 97 91 33 66 54
1998 2007
0-19 0-19
4 4
9.9 8.2
1987-1999 1977-2002 2010-2011
0-15 0-20 0-14
1 4 2
790 1652 973
United States United States Rochester, MN, United States Christchurch, New Zealand New Zealand
a
Age range in years of data applicable to children and youths. Not included are additional data from adults reported from some studies. Annual rate per 100 000 population. All rates age-adjusted to US 2000 population aged 0 to 19 years, except Hawley et al and Leibson et al. c Includes prehospital fatalities. d Excludes in-hospital fatalities. e Includes cases attended within and outside of hospital or hospital emergency departments. b
Where studies specified incidence rates for extended sequential time periods, data representing the most recent period of study were selected for this review. Finally, some data representing brain injuries treated in emergency departments were not included in summaries of incidence when these data were based on case definitions including ICD-9CM code 959.01.
Table 2. Median Male: Female Traumatic Brain Injury Incidence Rate Ratios. Age range Source of data Hospital emergency department11,16,32,34 Hospital19-21,23-25,27,33,35 Mortality28,29 All sources above
0-9 1.2 1.5 1.3 1.4
10-20 2.2 2.2 2.4 2.2
Findings Incidence Table 1 summarizes the annual incidence rates of traumatic brain injury among children and youths reported from 18 studies. Two studies, both from the United States, analyzed data from injuries attended in hospital emergency departments but not admitted to hospital.15,16 From these sources, the median estimate of annual incidence is 691 injuries per 100 000 population. Eleven studies of populations in North America, Europe, and Australia analyzed data from injuries admitted to hospital.17-27 From these, the median estimate of annual incidence is 74 injuries per 100 000 population. Two studies, both from the United States, analyzed mortality data from vital records.28,29 These analyses yielded a median annual rate of 9 fatal injuries per 100 000 population. Finally, 3 studies, from New Zealand and the United States, assessed data for all medically attended or fatal traumatic brain injuries,11,30,31 including
prehospital fatalities, hospitalizations, emergency department visits, as well as other physician office or clinic visits. These yielded a median annual rate of 973 injuries per 100 000. The figure describes age-specific incidence rates of traumatic brain injury, stratified by type of treatment received or data source. Using the median values of age-specific rates of the 18 studies noted above, children aged less than 5 years have the highest incidence of injuries treated in hospital emergency departments. In contrast, compared to younger children, youths aged 15 years and older have a higher incidence of injuries treated in hospital and a much higher incidence of fatal injury. Fifteen studies reported incidence rates of traumatic brain injury for females and males.11,16,19-21,23-25,27-29,32-35 The median values of male-female rate ratios derived from these studies appear in Table 2, stratified by age group and data source.
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
4
Journal of Child Neurology
Table 3. Median Proportions of Traumatic Brain Injury by Selected Cause. Cause (%) Age range
Motor vehicle or transport
Attended in hospital emergency departments or all medically 0-4 7 5-9 13 10-14 19 15 37 Attended in hospital inpatient services17,20,22,24,37,38,40 0-4 15 5-9 29 10-14 54 15 56 Fatal injuries only28,29 0-4 47 5-9 71 10-14 57 15 54
Falls
Sports or recreation
attended11,15,30-32,34,36,39,42 69 5 53 31 37 26 11 20 59 50 23 12
2 4 8 9
4 2 2 1
Combining reports derived from hospital emergency departments, hospital inpatient services, and mortality records, among younger children aged less than 10 years, the risk of injury in males exceeds that of females by a factor of 1.4, while among older children and youths the risk in males exceeds the risk in females by a larger factor of 2.2. These findings vary little when fatal injuries and injuries attended in emergency departments or hospitals are considered separately.
Cause Eighteen studies reported rates or proportions of traumatic brain injuries in children by cause.11,15,17,19,20,22,24,28–32,34,36-40 Table 3 describes the distribution of median percentages for selected leading causes derived from these studies. The distribution by cause is also stratified by age group and principal source of data. The findings may be summarized as follows. Among children aged less than 5 years, falls account for about two-thirds of injuries attended in emergency departments, a majority of injuries attended in hospital, and few fatalities. In this age group, motor vehicle–related incidents account for comparatively small proportions of injuries attended in emergency departments and hospital, but nearly half of fatalities. Among children aged 5 to 14 years whose injuries are attended in emergency departments, falls remain the leading cause, followed by sports or recreation-related injuries, followed by motor vehicle injuries. For those treated in hospital, the leading causes among 5- to 14-year-old children are falls and motor vehicle injuries, the latter accounting for the majority of injuries in older children. Finally, within this age range, motor vehicle incidents cause the majority of fatal injuries, followed by firearms. Among youths aged 15 years or older, whose injuries are attended in emergency departments, motor vehicle–related incidents are the leading cause of brain injury, followed by
Assault
Firearms
1 2 8 22 9 2 3 10 4 10 28 38
assault, followed closely by sports-related incidents. Among youths treated in hospital, a majority of injuries are attributed to motor vehicles. In this age group, most brain injury deaths are attributable either to motor vehicles or to firearms. One study focused entirely on the causes of hospitalized traumatic brain injuries in infants and very young children aged less than 2 years.37 The leading cause of such injury among infants aged less than 1 year was falls (72%), followed by assaultive or abusive head trauma (22%). The leading causes in 1-year-old children were falls (36%), followed by motorvehicle crashes (9%) and abusive head trauma (5%).
Residence Two studies compared risks of traumatic brain injury between children residing in rural and urban areas. In Minnesota, overall rates of injury resulting in hospitalization or death were only slightly higher among those residing in nonmetropolitan areas compared to those in metropolitan areas.26 However, the ratio of nonmetropolitan to metropolitan resident mortality rates was 2.4, a significant finding of higher risk of death among the former. In Colorado, among children and youths 5 to 24 years of age, combined rates of hospitalization and fatal injury were also significantly higher in rural residents compared to urban residents.41 Across all ages including adults, this effect was attributable in large part to differences in rates of motor vehicle–related injuries.
Severity Most studies did not describe the distribution of traumatic brain injuries by severity or did not describe this distribution separately for children. However, one study of statewide emergency department, hospitalization, and mortality data42 estimated less than 2% of nonfatal head injuries to children seen in emergency departments were in the serious-through-
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
Thurman
5
Table 4. Temporal Trends in Rates of Hospitalization and Death Associated With Traumatic Brain Injury. Study population
Interval
% change
Hospitalizations United States, all ages45 United States, children43 Canada, children44
1980-1995 1991-2005 1991-2005
–51.0 –39.0 –63.8
Mortality United States, all ages45,a United States, children43,a United States, all ages28,29
1980-1995 1991-2005 1998-2007
–17.0 –20.0 –17.2
a
In-hospital mortality only.
severe range (Abbreviated Injury Scale score 3 – 6), compared to 31% of such injuries admitted to hospital.a Another study of statewide data26 found that among head injuries in children admitted to hospital, 14% were serious (Abbreviated Injury Scale score 3), whereas 17% were severe (Abbreviated Injury Scale score 4 – 6).b Thus, the vast majority of nonfatal traumatic brain injuries to children evaluated in emergency departments can be regarded as mild, whereas a substantial proportion—nearly a third—of those hospitalized are serious to severe. Among specific causes of injury, using ‘‘falls and other mechanisms’’ as a point of comparison, firearms were most strongly associated with severe injury (odds ratio 88.5), followed by battering (odds ratio 8.6), all-terrain vehicle (odds ratio 8.0), motor vehicle (odds ratio 2.5), and ‘‘struck by objects or persons’’ (odds ratio 2.2).26
Temporal Trends Several studies from North America provided information on trends over time in the incidence of hospitalized or fatal traumatic brain injuries as summarized in Table 4.28,29,43-45 The studies indicated a marked reduction in brain injury hospitalization rates during the past 3 decades: nearly 50% from 1980 to 1995, with similar relative reductions from 1991 to 2005. Substantial though smaller reductions in the incidence of fatal brain injury were also found.
Discussion If we apply the median incidence rates found in this review to the 2014 US population less than 20 years of age,46 we can estimate that this year in the United States approximately 630 000 children and youths will be treated in emergency departments, 60 000 will be hospitalized, and 7500 will die with traumatic brain injury. However, for the following reasons, the data on which these findings are based provide an incomplete and imprecise indication of the burden of traumatic brain injury in the population of children. The inaccuracies of ICD-coded data, upon which most of these studies depend, have already been noted, adversely affecting both the sensitivity and the positive predictive value of case ascertainment. In addition, these data describe only
brain injuries that are medically attended or fatal, leaving a substantial proportion of brain injuries uncounted. According to a US population-based survey representing children and adults, 25% of respondents who reported a head injury with loss of consciousness in the past year indicated that they did not seek medical attention.39 Among children only, the proportion of unattended injuries was not described. While injuries for which medical care is sought might be regarded as generally more serious, it cannot be assumed that all of the many unattended injuries are necessarily inconsequential. For example, many sports-related concussions may not be medically attended. Furthermore, sports injuries are commonly repeated, increasing their potential for adverse long-term outcomes. A discussion of the risk of concussions and other traumatic brain injuries among children and youths engaging in sports and recreation is beyond the scope of this analysis but has been addressed in other reviews47 and in recent guidelines for their management.48 In addition, these data provide only crude indications of the distribution of these traumatic brain injuries by severity. More important, the sources for this review provide scant information about the long-term outcomes of traumatic brain injury in children, specifically the prevalence of consequent impairment and disability. Population-based follow-up studies of adults who have survived following hospitalization for brain injury provide estimates of long-term disability (defined grossly by reduced independence in basic or instrumental activities of daily living) among nearly 40% of survivors.49,50 One population-based Danish study assessed outcomes for a subset of children aged 10 to 14 years who were admitted to hospital between 1979 to 1981 with diagnoses of concussion, brain contusion, or traumatic intracranial hemorrhage.51 The study found that after approximately 15 years, about 20% of the survivors, now young adults, were receiving disability payments. While the overall prevalence of long-term impairment and disability among persons hospitalized in childhood with brain injury has not been established, a substantial burden may be assumed. The population prevalence of impairment and disability following brain injuries treated in emergency departments is unknown, although presumably far lower. As summarized in Table 3, the studies of mortality included in this review28,29 describe only broad categories of cause of injury. These, as well as most of the studies of brain injury morbidity, do not describe pediatric abusive head trauma as a separate category, a critical cause of injury and death in infants. To address the problem of underascertainment and underrecognition of this cause of injury, in 2012 the CDC published recommended case definitions (including indicative ICD-9-CM and ICD-10 code combinations) to identify these cases for epidemiologic studies and public health surveillance.52 Using these standardized definitions, subsequent analyses of representative health and vital data sets in the United States indicate that among children under 2 years of age, abusive head trauma accounts for 27% of all fatal head injuries53 and 21% of all hospitalized head injuries.54 Estimates of hospitalized abusive head trauma may be conservative, inasmuch as some cases
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
6
Journal of Child Neurology
Figure 1. Median estimates of annual traumatic brain injury incidence by age group and source of case report.
cannot be determined because of missing external-cause-ofinjury codes in nearly 10% of head injury records. Clearly, such trauma among infants merits closer attention in future epidemiologic studies. The findings of decreasing rates of hospitalization and death associated with brain injury require interpretation. The reductions in hospitalization appear to arise primarily from criteria enacted in recent years that disproportionately restrict the admission of less severe injuries,45 which presumably are now managed mainly in emergency departments. In addition, a reduced occurrence of all injuries, including brain injuries, has followed successes in injury prevention, especially with improved motor vehicle safety.55 The reductions in death rates associated with brain injury, which are proportionately less than the reductions in hospitalization rates, can be attributed both to injury prevention and to improved medical treatment.
restraints designed for children are effective.56 Therefore, to promote the proper use of child restraints, advocacy of effective public policies as well as more effective education methods for parents are still needed. Among fatal traumatic brain injuries in the United States, firearms rank close to motor vehicles as the next leading agent of injury among older children and youths, a finding that should not be generalized to other high-income countries whose policies are more restrictive of the availability of firearms. In principle, the advocacy and adoption of effective policies to reduce the availability and prevalence of firearms—especially their availability to children and youth— could prevent many of these injuries, notwithstanding current political barriers to their enactment in the United States. Among the causes of less severe traumatic brain injuries, and among younger children, falls predominate, followed by sports and recreation. The circumstances and direct agents of these injuries are manifold, requiring more varied strategies for prevention, sometimes involving personal protective equipment or close attention to the engineering of playground equipment and surfaces.57 Recent guidelines on the management of concussion in sports address some of these issues, including the prevention of injury recurrences.48 The subject of sports-related concussions in youth is also addressed in depth in a recent report of the Institute of Medicine, including recommendations for improved public health surveillance.58 The large public health burden of traumatic brain injury in children clearly justifies greater investment in research on effective methods for their prevention as well as more effective methods for their acute treatment and rehabilitation. With this, continued surveillance and epidemiologic research is necessary as well, with special attention not only to incidence, risk factors, and more specific causes, but also to the longerterm outcomes of these injuries. Declaration of Conflicting Interests The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author received no financial support for the research, authorship, and/or publication of this article.
Conclusions The incidence of traumatic brain injury in children and youths is high, and substantial numbers of those affected incur severe consequences including death or disability. Accordingly, these injuries merit focused attention from neurologists, other health care professionals, and indeed communities at large, with the goals of advancing their prevention as well as their treatment. Prevention has the potential for even greater benefit than improved treatment. Among more severe injuries, 2 underlying causes stand out as important opportunities for prevention. Motor vehicle collisions are still the most common cause, despite improvements in vehicle design and road safety during the past half century. A high proportion of child passengers killed in motor vehicle crashes are still unrestrained or improperly restrained, despite evidence that passenger
Notes a. These estimates of the proportion of severe injury rely on computer-generated approximations to the Abbreviated Injury Scale for the head region (‘‘ICDMAP’’), based on information from ICD-9-CM coded diagnoses, which include indicators of loss of consciousness as well as cranial and intracranial traumatic lesions. In the Abbreviated Injury Scale system, a score of 3 is characterized as ‘‘serious’’ (or ‘‘severe but not life-threatening’’), whereas scores of 4 to 6 are characterized as ‘‘severe,’’ ‘‘critical,’’ or ‘‘maximum’’ (representing increasing levels of risk of death). It should be noted that the ICD-9-CM-based case definition used in this study included code 959.01 (head injury, unspecified), thus including some superficial head injuries that would not meet the clinical definition of traumatic brain injury.
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
Thurman
7
b. These estimates rely on Abbreviated Injury Scale scoring based on a review of the original medical records of cases.
References 1. Murray CJ, Lopez AD. Global Health Statistics. Geneva: World Health Organization; 1996. 2. World Health Organization. Neurological Disorders: Public Health Challenges. Geneva: World Health Organization; 2006. 3. Kraus JF, Rock A, Hemyari P. Brain injuries among infants, children, adolescents, and young adults. Am J Dis Child. 1990; 144:684-691. 4. Thurman DJ, Kraus JF, Romer CJ, eds. Standards for Surveillance of Neurotrauma. Geneva: World Health Organization; 1996. 5. Thurman DJ, Sniezek JE, Johnson D, Greenspan A, Smith SM. Guidelines for Surveillance of Central Nervous System Injury. Atlanta: Centers for Disease Control and Prevention; 1995. 6. World Health Organization. International Classification of Diseases, 9th Revision. Geneva: World Health Organization; 1977. 7. World Health Organization. International Classification of Diseases, Tenth Revision. Geneva: World Health Organization; 1992. 8. US Department of Health and Human Services. Interntional Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM]. Washington, DC: US Department of Health and Human Services; 1979. 9. Rodriguez SR, Mallonee S, Archer P, Gofton J. Evaluation of death certificate-based surveillance for traumatic brain injury— Oklahoma 2002. Public Health Rep. 2006;121:282-289. 10. Bazarian JJ, Veazie P, Mookerjee S, Lerner EB. Accuracy of mild traumatic brain injury case ascertainment using ICD-9 codes. Acad Emerg Med. 2006;13:31-38. 11. Leibson CL, Brown AW, Ransom JE, et al. Incidence of traumatic brain injury across the full disease spectrum: a population-based medical record review study. Epidemiology. 2011;22:836-844. 12. US Department of Health and Human Services. ICD-10-CM Tabular List of Diseases and Injuries. International Classification of Diseases, Tenth Revision, Clinical Modification. Washington, DC: US Department of Health and Human Services; 2014. 13. Teasdale G, Jennett B. Assessment of coma and impaired consciousness: a practical scale. Lancet. 1974;2:81-84. 14. Gennarelli TA, American Association for Automotive Medicine. Committee on Injury Scaling. The Abbreviated Injury Scale. Des Plaines, IL: American Association for Automotive Medicine; 1985. 15. Guerrero JL, Thurman DJ, Sniezek JE. Emergency department visits associated with traumatic brain injury: United States, 1995-1996. Brain Inj. 2000;14:181-186. 16. Jager TE, Weiss HB, Coben JH, Pepe PE. Traumatic brain injuries evaluated in U.S. emergency departments, 1992-1994. Acad Emerg Med. 2000;7:134-140. 17. Asemota AO, George BP, Bowman SM, Haider AH, Schneider EB. Causes and trends in traumatic brain injury for United States adolescents. J Neurotrauma. 2013;30:67-75. 18. Baldo V, Marcolongo A, Floreani A, et al. Epidemiological aspect of traumatic brain injury in Northeast Italy. Eur J Epidemiol. 2003;18:1059-1063.
19. Berry JG, Jamieson LM, Harrison JE. Head and traumatic brain injuries among Australian children, July 2000-June 2006. Inj Prev. 2010;16:198-202. 20. Centers for Disease Control and Prevention. Traumatic brain injury—Colorado, Missouri, Oklahoma, and Utah, 1990-1993. MMWR Morb Mortal Wkly Rep. 1997;46:8-11. 21. Colantonio A, Saverino C, Zagorski B, et al. Hospitalizations and emergency department visits for TBI in Ontario. Can J Neurol Sci. 2010;37:783-790. 22. Hawley CA, Ward AB, Long J, Owen DW, Magnay AR. Prevalence of traumatic brain injury amongst children admitted to hospital in one health district: a population-based study. Injury. 2003; 34:256-260. 23. Koskinen S, Alaranta H. Traumatic brain injury in Finland 1991-2005: a nationwide register study of hospitalized and fatal TBI. Brain Inj. 2008;22:205-214. 24. Langlois JA, Kegler SR, Butler JA, et al. Traumatic brain injuryrelated hospital discharges. Results from a 14-state surveillance system, 1997. Morb Mortal Wkly Rep Surveill Summ. 2003;52:1-20. 25. Piatt JH Jr, Neff DA. Hospital care of childhood traumatic brain injury in the United States, 1997-2009: a neurosurgical perspective. J Neurosurg Pediatr. 2012;10:257-267. 26. Reid SR, Roesler JS, Gaichas AM, Tsai AK. The epidemiology of pediatric traumatic brain injury in Minnesota. Arch Pediatr Adolesc Med. 2001;155:784-789. 27. Schneier AJ, Shields BJ, Hostetler SG, Xiang H, Smith GA. Incidence of pediatric traumatic brain injury and associated hospital resource utilization in the United States. Pediatrics. 2006;118:483-492. 28. Adekoya N, Thurman DJ, White DD, Webb KW. Surveillance for traumatic brain injury deaths—United States, 1989-1998. Morb Mortal Wkly Rep Surveill Summ. 2002;51:1-14. 29. Coronado VG, Xu L, Basavaraju SV, et al. Surveillance for traumatic brain injury-related deaths—United States, 1997-2007. Morb Mortal Wkly Rep Surveill Summ. 2011;60:1-32. 30. Feigin VL, Theadom A, Barker-Collo S, et al. Incidence of traumatic brain injury in New Zealand: a population-based study. Lancet Neurol. 2013;12:53-64. 31. McKinlay A, Grace RC, Horwood LJ, Fergusson DM, Ridder EM, MacFarlane MR. Prevalence of traumatic brain injury among children, adolescents and young adults: prospective evidence from a birth cohort. Brain Inj. 2008;22:175-181. 32. Dahl E, von Wendt L, Emanuelson I. A prospective, populationbased, follow-up study of mild traumatic brain injury in children. Injury. 2006;37:402-409. 33. Perez K, Novoa AM, Santamarina-Rubio E, et al. Incidence trends of traumatic spinal cord injury and traumatic brain injury in Spain, 2000-2009. Accid Anal Prev. 2012;46:37-44. 34. Pickett W, Ardern C, Brison RJ. A population-based study of potential brain injuries requiring emergency care. CMAJ. 2001; 165:288-292. 35. Tieves KS, Yang H, Layde PM. The epidemiology of traumatic brain injury in Wisconsin, 2001. WMJ. 2005;104:22-25, 54. 36. Bazarian JJ, McClung J, Shah MN, Cheng YT, Flesher W, Kraus J. Mild traumatic brain injury in the United States, 1998–2000. Brain Inj. 2005;19:85-91.
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
8
Journal of Child Neurology
37. Eisele JA, Kegler SR, Trent RB, Coronado VG. Nonfatal traumatic brain injury-related hospitalization in very young children—15 states, 1999. J Head Trauma Rehabil. 2006; 21:537-543. 38. Koepsell TD, Rivara FP, Vavilala MS, et al. Incidence and descriptive epidemiologic features of traumatic brain injury in King County, Washington. Pediatrics. 2011;128:946-954. 39. Sosin DM, Sniezek JE, Thurman DJ. Incidence of mild and moderate brain injury in the United States, 1991. Brain Inj. 1996;10:47-54. 40. Thurman DJ, Jeppson L, Burnett CL, Beaudoin DE, Rheinberger MM, Sniezek JE. Surveillance of traumatic brain injuries in Utah. West J Med. 1996;165:192-196. 41. Gabella B, Hoffman RE, Marine WW, Stallones L. Urban and rural traumatic brain injuries in Colorado. Ann Epidemiol. 1997; 7:207-212. 42. McCarthy ML, Serpi T, Kufera JA, Demeter LA, Paidas C. Factors influencing admission among children with a traumatic brain injury. Acad Emerg Med. 2002;9:684-693. 43. Bowman SM, Bird TM, Aitken ME, Tilford JM. Trends in hospitalizations associated with pediatric traumatic brain injuries. Pediatrics. 2008;122:988-993. 44. Colantonio A, Croxford R, Farooq S, Laporte A, Coyte PC. Trends in hospitalization associated with traumatic brain injury in a publicly insured population, 1992-2002. J Trauma. 2009;66:179-183. 45. Thurman D, Guerrero J. Trends in hospitalization associated with traumatic brain injury. JAMA. 1999;282:954-957. 46. CDC Wonder. Census population information. http://wonder.cdc. gov/population.html. Accessed October 24, 2013. 47. Thurman DJ, Branche CM, Sniezek JE. The epidemiology of sports-related traumatic brain injuries in the United States: recent developments. J Head Trauma Rehabil. 1998;13:1-8. 48. Giza CC, Kutcher JS, Ashwal S, et al. Summary of evidence-based guideline update: evaluation and management of concussion in sports: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2013;80: 2250-2257.
49. Selassie AW, Zaloshnja E, Langlois JA, Miller T, Jones P, Steiner CJ. Incidence of long-term disability following traumatic brain injury hospitalization, United States, 2003. J Head Trauma Rehabil. 2008;23:123-131. 50. Whiteneck G, Brooks CA, Mellick D, Harrison-Felix C, Terrill MS, Noble K. Population-based estimates of outcomes after hospitalization for traumatic brain injury in Colorado. Arch Phys Med Rehabil. 2004;85(4 suppl 2):73-81. 51. Engberg A, Teasdale TW. Traumatic brain injury in children in Denmark: a national 15-year study. Eur J Epidemiol. 1998;14: 165-173. 52. Parks SE, Annest JL, Hill HA, Karch DL. Pediatric Abusive Head Trauma: Recommended Definitions for Public Health Surveillance and Research. Atlanta: Centers for Disease Control and Prevention; 2012. 53. Parks SE, Kegler SR, Annest JL, Mercy JA. Characteristics of fatal abusive head trauma among children in the USA: 2003-2007: an application of the CDC operational case definition to national vital statistics data. Inj Prev. 2012;18:193-199. 54. Parks S, Sugerman D, Xu L, Coronado V. Characteristics of non-fatal abusive head trauma among children in the USA, 2003–2008: application of the CDC operational case definition to national hospital inpatient data. Inj Prev. 2012;18:392-398. 55. Dellinger AM, Sleet DA, Jones BH. Drivers, wheels, and roads: motor vehicle safety in the twentieth century. In: Ward JW, Warren C, eds. Silent Victories: the History and Practice of Public Health in Twentieth-century America. New York: Oxford; 2007:343-362. 56. Barraco RD, Cheng JD, Bromberg WJ, et al. Child passenger safety: an evidence-based review. J Trauma. 2010;69: 1588-1590. 57. Centers for Disease Control and Prevention—National Center for Injury Prevention and Control. National Action Plan for Child Injury Prevention. Atlanta: CDC, NCIPC; 2012. 58. Institute of Medicine and National Research Council. Concussions in Youth: Improving the Science, Changing the Culture. Washington, DC: National Academies Press; 2013.
Downloaded from jcn.sagepub.com at FLORIDA INTERNATIONAL UNIV on August 31, 2014
