Objective To describe the rates of hospitalisation for head and traumatic brain injury among Australian children aged 0–14 years.
Design Descriptive analysis of the Australian Institute of Health and Welfare National Hospital Morbidity Database, using data for the period 1 July 2000 to 30 June 2006.
Results The rate of hospitalisation for head injury was 395.9 per 100 000 (95% CI 393.4 to 398.4), with 47.6 per 100 000 (95% CI 46.7 to 48.5) being high-threat-to-life injuries. In multivariate analysis, those aged 0–4 years had 1.8 times the rate of head injury of 10–14-year-olds, while boys had 1.7 times the rate of girls. Children living in very remote and remote areas had a 1.3–1.5-fold greater rate of head injury, and a 1.6–1.8-fold greater rate of injuries that were high threat to life, than city-dwelling children. The rate of traumatic brain injury (TBI) was 91.1 per 100 000 (95% CI 89.9 to 92.3), with 34.7 per 100 000 (95% CI 33.9 to 35.4) being high-threat-to-life injuries. In multivariate analysis, children aged 0–4 years had 0.8 times the rate of 10–14-year-olds, and boys had 1.9 times the rate of girls. Children living in the very remote and remote areas had a 1.9–2.8-fold greater rate of TBI, and a 1.5–1.7-fold greater rate of injuries that were high threat to life, than city-dwelling children.
Conclusions Children living remotely were disproportionately represented among those sustaining head injuries. Almost a quarter of head injuries were TBI.
- head injury
- traumatic brain injury
- rural health
- public health
- safe community
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- head injury
- traumatic brain injury
- rural health
- public health
- safe community
Injury is a leading cause of mortality and the most common cause of death among children in Australia and other countries.1–4 While most head injuries sustained by children are of modest severity, many can affect behavioural and emotional development.5 Studies of outcomes 2 years after injury show that traumatic brain injury (TBI) in childhood can lead to psychiatric problems, difficulties in adaptive functioning, and deficits in academic and cognitive skills.6 The societal cost of childhood disability following head injury can consequentially be substantial, as services may need to be provided on a long-term, sometimes life-long, basis.7
There is little documentation of the nature of head injuries sustained among Australian children; thus the aim of this study was to describe hospitalised head injury among 0–14-year-olds in relation to age group, sex and location.
National data on children aged 0–14 years who received inpatient care for a head injury at public and private hospitals, between 1 July 2000 and 30 June 2006, were obtained from the Australian Institute of Health and Welfare (AIHW) National Hospital Morbidity Database. Data were coded according to the International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Australian Modification (ICD-10-AM). Records were selected if the principal or any additional diagnosis fields contained an ICD-10-AM code of ‘injury to the head’ (S00–S09). We followed the Centers for Disease Control and Prevention's case definition of TBI,8 after translation from ICD-9-CM (codes 800.0–801.9, 803.0–804.9, and 850.0–854.1) to ICD-10-AM codes (S02.0–S02.1, S02.7–S02.9, S06.0–S06.9).
Head injuries with a high threat to life were specified using the ICD-based Injury Severity Score (ICISS) method and a source of survival weights for each ICD-10-AM injury code.9 Each patient's ICISS is the product of the survival weight for each of their injury diagnosis codes, lower scores representing more severe injuries. Patients with an ICISS ≤0.941 were defined as having high threat to life.10 11 Incident cases of injury were approximated by excluding separations in which the mode of admission was inward transfer from another acute care hospital. The mechanism of injury was categorised according to the first reported external cause code in the record (ICD-10-AM range V01–Y98).
Estimated resident population counts for the mid-point of a fiscal year (31 December) were interpolated from the two flanking estimates as at 30 June, obtained from the AIHW. Residential location was grouped using the Australian Bureau of Statistics Australian Standard Geographical Classification, categorised as major cities, inner regional, outer regional, remote and very remote.12 Remoteness is measured in terms of road distance from a person's place of usual residence to five categories of service centres that are ranked by population size,13 thus providing an indication of accessibility to a wide range of goods and services, including health-related services and facilities, and opportunities for social interaction.12 Comparisons of the external cause of the first reported head injury, stratified by remoteness, were performed using a χ2 test. Annual average head injury incidence rates and incident rate ratios were computed along with 95% CIs using a generalised Poisson regression model.14 Data were analysed using Stata V9.2 statistical software.
During the study period, 95 485 hospitalised head injury cases occurred at ages 0–14 years, accounting for 17.8% of total head injury cases (n=536 420). The most prevalent first reported diagnosis was open wound to the head (n=32 195; 33.7%). The two most common mechanisms of head injury were falls and transport (table 1). The subset defined as TBI accounted for 23.0% of child head injury cases; four-fifths were caused by falls and transport crashes.
About 60% of head injury cases occurred in Australia's major cities (table 1). Falls were a more prominent cause of head injury in city-dwelling children than among children who lived outside of major cities, whereas transport featured more prominently as a cause of head injury among children who lived outside of major cities than among city-dwelling children (p<0.001). The same pattern was observed for TBI (p<0.001).
The rate of hospitalised head injury was 395.9 per 100 000, while the rate of head injury considered a high threat to life was 47.6 per 100 000 (table 2). There was a small, but significant, decline in the rate of high-threat-to-life head injury over time, but not for total head injury. After adjustment for other covariates, those aged 0–4 years had 1.8 times the rate of head injury of their 10–14-year-old counterparts, while boys had 1.7 times the rate of girls. For head injuries that were high threat to life, children aged 0–4 years had 1.1 times the rate of 10–14-year-olds, and boys had 1.9 times the rate of girls, after adjustment for other covariates. The rate of head injury significantly increased with remoteness of usual residence; children living in remote and very remote areas had 1.5 and 1.3 times the rate of children living in major cities. A similar pattern occurred for high-threat-to-life cases; children living in remote and very remote areas had 1.8 and 1.6 times the rate of children living in major cities.
The rate of TBI was 91.1 per 100 000, while the rate of TBI considered a high threat to life was 34.7 per 100 000 (table 3). There was a significant decline in the rate of TBI, and the rate of high-threat-to-life TBI, over time. In multivariate analysis, children aged 0–4 years had 0.8 times the rate of TBI of their 10–14-year-old counterparts, and boys had 1.9 times the rate of girls. For high-threat-to-life TBI, children aged 0–4 years had 1.2 times the rate of 10–14-year-olds, and boys had 1.9 times the rate of girls. The rate of TBI significantly increased with remoteness of usual residence; children living in remote and very remote areas had 2.8 and 1.9 times the rate of children living in major cities. Children living in remote and very remote areas had 1.7 and 1.5 times the rate of TBI that was high threat to life, compared with children living in major cities.
Boys had a greater rate of head injury than their female counterparts at 0–4 years (1.4-fold), 5–9 years (1.6-fold) and 10–14 years (2.6-fold) (figures 1 and 2). The same pattern was observed for TBI and for the subsets of these conditions that were high threat to life. Among boys, those aged 0–4 years had the highest rate of total head injury, whereas boys aged 10–14 years had the highest rate of TBI and head injuries considered to be a high threat to life. Among girls, those aged 0–4 years had the highest rates of total head injury, TBI and head injuries considered to be a high threat to life.
Children aged 0–14 years accounted for about one in five hospital admissions for head injury in Australia in the 6 years from 1 July 2000 to 30 June 2006. Almost a quarter of head injuries were TBI. High-threat-to-life injuries accounted for ∼10% of all head injury admissions for children aged 0–14 years, and over one-third of the TBI cases. There were some signs of a declining trend for head injury that was high threat to life, but not total head injury, whereas TBI and high-threat-to-life TBI both showed rate reductions over time.
The rates of head injury, particularly TBI, were higher among remote-dwelling children compared with their urban counterparts. Distance and remoteness may raise the risk of certain injuries (eg, transport) and hamper rapid retrieval of injured children to acute care services, as well as complicate later stages of care and rehabilitation. The higher rates of child head injuries in remote and very remote areas compared with major cities may be explained, to some extent, by the higher proportion of Indigenous Australians living remotely, and their experience of excess morbidity and mortality from injury compared with other Australians.15 16
Similar to other studies,17–19 we found that, in each age group, boys had higher rates of head injury and TBI than girls; this was also true for head injuries and TBI that were high threat to life. The differences emerge at a young age, which can perhaps be attributed to differences in play patterns and physical development.20 While age-appropriate supervision remains important to ensure that children follow safe rules for play, environmental prevention measures, such as rigorous implementation of playground equipment standards, are also important.21 22
While the rate of hospitalised head injury was markedly higher in the youngest age group, there was less variation by age in the high-threat-to-life subset. This may indicate that children in the youngest age group are more vulnerable to head injuries than older children, but the excess is mainly ‘low-threat’ cases, or that there is a greater likelihood for parents to instigate precautionary attendance at hospitals for head injuries that occur in younger children. There is a paucity of research investigating whether child age influences the likelihood of presenting, and being admitted, to hospital for head injury. A retrospective study of 0–16-year-olds who presented to the emergency department, or were directly admitted to an Australian hospital, after a head injury found that half the children were 3 years of age or younger.23 However, no data were presented on whether admission for mild head injuries was more common among younger than older children. A study of moderate and severe hospitalised paediatric trauma in England and Wales found that, with increasing age, there was a decline in the proportion of children with head injury and an increase in the proportion with limb injury,4 but no population-based incidence rates were presented, limiting the inferences that could be made.
This study was cross-sectional in design. Thus it provides a descriptive analysis of the epidemiology of paediatric head injury in Australia, but it cannot examine the long-term outcomes of head injury and TBI.24 25 The data exclude presentations at emergency departments that do not result in an admission to hospital. While the codes for TBI were translated from an ICD-9-CM-based definition,8 a good match can be achieved; most of the injuries defined as TBI according to ICD-9-CM would also be defined as TBI when mapped to ICD-10-AM.
Even apparently minor trauma to the head can result in important intracranial injury.26
Given the direct and associated costs of treating head injuries among children, reducing the risk of such trauma is of public health importance. More research is required to provide greater insight into the reasons for the disparity by residential location, age group and sex, thus informing the design, evaluation and monitoring of effective head injury prevention programs.
What is already known on this subject
Injury is a leading cause of mortality and the most common cause of death among children.
Many child head injuries affect behavioural and emotional development.
Minor trauma to the head can result in important intracranial injury.
The societal cost of childhood disability following head injury can be substantial.
What this study adds
Remote-dwelling children in Australia were disproportionately represented among those sustaining head injuries, along with boys and pre-schoolers.
A third of head injury cases were open wounds to the head, and almost a quarter were traumatic brain injury (TBI).
High-threat-to-life injuries accounted for ∼10% of all head injury admissions and over one-third of the TBI cases.
There was a downward trend in TBI, including high-threat-to-life TBI, in the 6 years from 1 July 2000 to 30 June 2006.
The analysis in this paper is based on hospital data provided by the Australian Institute of Health and Welfare (AIHW). The results and interpretations presented in the paper are those of the authors, and not the AIHW.
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.
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