Concussions in Australia over the last decade

Introduction

There is rising global concern about concussions (see Box CON.1) and their long-term health effects. Especially within a sporting context, new research highlights the links between repeated concussions and permanent impacts on cognitive, behavioural and social functioning (Bannon et al. 2020; Chase et al. 2020; Walton et al. 2022). 

With sport contributing substantially to the Australian identity, identifying and assessing the impacts of concussion on the sporting field is essential to prevent injury, optimise athlete performance and health, and reduce burdens on the health system. 

Numerous Australian sporting associations and academic institutions have invested substantial resources into improving player safety, including:

• injury surveillance research
• athlete educational programs
• return-to-play guidelines (AFL 2021; ASC 2024; Ignacy et al. 2021; Spiegelhalter et al. 2023). 

An Australian Senate inquiry in 2023 explored concussions and repeated head trauma in contact sports (Senate Community Affairs References Committee 2023). However, data presented here show that sports are involved in just over 1 in 5 concussion hospitalisations in Australia. 

It is important not to focus solely on the sporting context. Half of all concussion hospitalisations in 2021–22 were caused by falls, and a quarter by transport accidents (including while in a car, and on a motorcycle or bicycle). Sport in this report is classed as an activity, not a cause group (see Box CON.2). As such, a concussion hospitalisation involving sport will still have a separate cause assigned, such as a fall. Assessing concussions that occur both on and off the sporting field is necessary to minimise instances of both acute injury and long-term consequences of concussions (see Box CON.2).

Having as few as 3 concussions can contribute to cognitive decline in later life (Lennon et al. 2023); however, the number of reported cases of people suffering long-term effects from concussion is a very small proportion of reported concussion cases (QBI 2024). Sub-concussive impacts are considered potentially injurious despite the absence of symptoms (Daneshvar et al. 2023). Concussions have far-reaching impacts not only for the individual, but also for health systems and the wider community. It is estimated that over $50 million is spent on concussion-related hospital admissions across Australia’s health system each year (Thomas et al. 2020) (see Box CON.3).

Data set limitations

Concussions are under-reported within both medical and sporting settings. Contributing factors include lack of education, different definitions of concussion, and a competitive sporting culture that promotes a ‘play on’ mentality (Leeds et al. 2022; Longworth et al. 2021; Senate Community Affairs References Committee 2023). The Australian Institute of Sport (2023) estimates that concussion under-reporting can be up to 82% across certain sports. 

While research has mainly focused on concussion under-reporting in sport, Foster and colleagues (2019) suggest that a culture of concussion non-disclosure is not limited to athletes. Hence, numbers presented in this article are likely to be a substantial under‑representation of the true numbers of concussions across Australia.

The data sets used in comparing sports have limitations. Not all ED presentation records have activity information, meaning that sport involvement across injuries cannot be completely determined. In hospitals, over half of concussion cases do not have any activity information recorded (54%), so findings related to activity at the time of injury should be interpreted with caution. In the sport context, it is important to take into account exposure, such as participation rates reported through AusPlay ^TM – a large population tracking survey funded and led by the Australian Sports Commission. These rates are based on survey data, so are subject to sampling error. Consequently, rates of concussion per 100,000 participants should be treated as estimates.

ED presentations for concussions on the rise, while hospitalisations decline

In 2021–22, there were 17,700 ED presentations for concussions (72 per 100,000 population). Between 2014–15 and 2021–22, ED presentation rates for concussions increased by an average of 5.4% per year. Notably in 2020–21, ED presentation numbers saw a 34% increase, following a period of stagnation (Figure CON.1). This increase is likely attributed, in part, to the easing of COVID-19 restrictions across Australia; however, it is still larger than expected relative to pre-pandemic trends. Total ED presentations increased by 6.9% in 2020–21 (AIHW 2023c). 

Improved community awareness, as well as updated return-to-play guidelines for concussion, may be factoring into the rapid increase in concussion ED presentations (Thomas et al. 2020). Changing trends in triage categories could be reflecting this (see the section headed ‘What is the severity of concussions?’ later in this article). There have been no ICD coding changes to explain this phenomenon.

Figure CON.1: Rates of ED presentation for concussion are increasing over time

Source: AIHW National Non-Admitted Patient Emergency Department Care Database.

While ED presentations for concussions are on the rise, this is not being reflected in hospital admissions:

• In 2021–22, there were 10,700 concussion hospitalisations (42 per 100,000). 
• Between 2012–13 and 2016–17, hospitalisation rates for concussions rose by an average of 6.4% per annum, from 41 to 53 per 100,000 population.
• Between 2017–18 and 2021–22, this trend reversed, with hospitalisations falling by an average of 3.2% per year (Figure CON.2). All injury hospitalisations also fell during this period (AIHW 2023e). COVID-19 is likely contributing to the volatility seen in figure CON.2.

The Australian Institute of Sport and the Australian Medical Association Concussion in Sport Position Statement may have informed concussion management practices in EDs in stating that:

• most concussion symptoms resolve spontaneously, given appropriate management
• the main management approach is rest, without need for further medical intervention.

Changing trends in ED end status (see Figure CON.8) may be reflecting the application of this advice.

Figure CON.2: Rates of hospitalisation for concussion have fallen over the past 5 years

Note: Hospitalisation data are divided into 2 time periods: 2012–13 to 2016–17, and 2017–18 to 2021–22. Comparing hospitalisations data for these 2 periods is not recommended due to a change in data collection methods between 2016–17 and 2017–18 (see Injury in Australia technical notes for more details).

Source: AIHW National Hospital Morbidity Database.

Males and people aged 15–24 have the highest rates of concussion

Males consistently have higher overall rates of injury than females (AIHW 2023e). Concussions are no exception and, in 2021–22, males:

• made up 60% of concussion hospitalisations and 59% of concussion ED presentations
• had the highest numbers and rates of concussion across all age groups. The key exception was women aged 65 and over, who have higher numbers and rates of concussion ED presentations.

Factors contributing to the higher rates of injuries among males could include the increased likelihood of:

• participating in risk-taking behaviours (Mollayeva et al. 2018)
• substance use/abuse (AIHW 2023a)
• occupational exposures and hazards (Safe Work Australia 2023).

Adolescents and young adults tend to be over-represented in concussions compared with all injuries, where rates of injury peak in older age groups (AIHW 2023e). People aged 15–24 had the highest rates of concussion ED presentations and hospitalisations (135 and 72, respectively, per 100,000 population) (see Figures CON.3 and CON.4).

Concussion among children

Developing brains are more vulnerable to concussion impacts, and children and adolescents appear to require longer periods of recovery time than adults (Manzanero et al. 2017; Parker et al. 2021). Younger age groups also have thinner skulls and less well-established neck muscles, both of which act as supporting structures to cushion the brain from impact (van Ierssel et al. 2021). 

For ED presentations, boys aged 5–14 had the highest rates of concussion of any age group across the population (165 per 100,000) (Figure CON.3). Males aged 15–24 had the highest rate of hospitalisation for concussion, with 91 per 100,000 – nearly double the rate of their female counterparts (51 per 100,000) (Figure CON.4). 

Figure CON.3: Children and young people have higher rates of concussion ED presentation

Figure CON.4: Children and young people have higher rates of concussion hospitalisation

Falls caused half of all concussion hospitalisations

The leading causes (termed ‘external causes’ in hospital records) of concussion hospitalisations in 2021–22 were:

• falls (50%)
• transport crashes (24%)
• assault (11%) (Figure CON.5).

Separate to the cause of the injury, the activity undertaken at the time of the injury was also recorded in just over half of the injury cases. Sport is classed as an activity, not an external cause. For information on sports-related concussions, see the section headed ‘1 in 5 concussion hospitalisations involve sport’ later in this article.

Figure CON.5: Falls are the leading cause of concussion hospitalisations

Notes

1. ‘Other causes’ includes Drowning and submersion, Choking and suffocation, Accidental poisoning, Electricity and air pressure, Forces of nature, Overexertion, Other specified and Undetermined intent.
2. For information on the grouping of external cause ICD-10-AM codes, see Injury in Australia technical notes.

Source: AIHW National Hospital Morbidity Database.

Falls

Falls caused the largest number of concussion hospitalisations (50%). This is similar to the pattern for total injuries, where falls are also the leading external cause of hospitalisations (43%) (AIHW 2023e). The most commonly specified types of falls were a fall:

• on the same level, including slipping, tripping, stumbling, or colliding with or being pushed by another person (53%)
• involving furniture (8.3%)
• on or from stairs or steps (6.4%).

Among hospitalisations for concussion caused by falls, the group aged 0–4 had the highest rate (42 per 100,000) followed closely by the 65 and over age group (39 per 100,000).

Transport crashes

Transport crashes are the second leading cause of concussion hospitalisations and the third leading cause of total injury hospitalisations (AIHW 2023h). Concussions made up around 4% of all transport injury hospitalisations (2,600) in 2021–22. Of these:

• nearly 3 in 10 (29%) were car occupants
• over one-quarter (27%) were pedal cyclists
• around one-fifth (19%) were motorcycle riders.

Assault

Assault is the third leading cause of concussion hospitalisations and the seventh leading cause of total injury hospitalisations (AIHW 2023e). Concussion hospitalisations made up around 6% of all assault injury hospitalisations (1,100) in 2021–22.

Males represented 65% of concussion hospitalisations related to assault. Where specified, females were more likely to have been assaulted by spouses or domestic partners (92%). Males were more likely to report being assaulted by an unknown person/s (86%). 

Over one-third of all assault-related concussion hospitalisations did not have a perpetrator recorded. This information may be unavailable for a number of reasons, including because it was not:

• reported by, or on behalf of, victims
• documented in the hospital record (AIHW 2019). 

Disclosure of the perpetrator in a hospital setting can be influenced by personal feelings such as fear or shame, insufficient recovery, insufficient privacy and time to disclose, and the extent of appropriate staff training and procedures that support disclosure.

Nearly 3 in 5 concussion hospitalisations involved a loss of consciousness

Loss of consciousness is an important factor in determining the severity of a concussion. Concussions involving a loss of consciousness have been shown to have poorer recovery outcomes than those with no loss of consciousness (Roy et al. 2020), though a large prospective cohort study of cognitive outcomes at one year follow up did not support an association (Schneider et al. 2022).

In 2021–22, 59% of concussion hospitalisations involved a loss of consciousness. Loss of consciousness (<30 minutes) (S06.02) was the most frequent principal diagnosis (4,500 diagnoses).

Males were more likely to have lost consciousness for any duration during a concussion incident than females (31 and 18 per 100,000). People aged 15–24 had the highest rate of loss of consciousness (40 per 100,000), followed by people aged 65 and over (34 per 100,000).

It has been estimated that loss of consciousness occurs in only around 10% of concussions in community sport football codes (Ractliffe et al. 2021). Of ED presentations, 28% of concussions involved a loss of consciousness. Comparatively, 59% of hospitalised concussion cases involved a loss of consciousness overall, and 51% of sports-related hospitalised concussion cases. This potentially represents people with more severe cases of concussion being admitted to hospital.

1 in 5 concussion hospitalisations involve sport

Of hospitalised concussion cases, 2,300 or 22% occurred while participating in sport or physical activity. The place where the injury occurred was specified for 74% of all concussion hospitalisations. Where specified, 17% of these occurred in a sports or athletics area (see Box CON.4).

Of the 2,300 concussion hospitalisations involving sport or physical activity:

• 1,600 were for males (69%)
• around 910 occurred while playing some form of rugby or football (including Australian Rules Football, rugby union, rugby league, soccer, and touch football) (39%)
• around 425 occurred while participating in a form of cycling (18%) (including BMX, mountain, road and velodrome cycling).

Similar to all concussion hospitalisations, younger age groups have the highest rates of hospitalisation. People aged 15–24 had the highest rate of concussion hospitalisations involving sport (27 per 100,000 population), followed by 5–14-year-olds (24 per 100,000). Children and adolescents have a higher risk of long-term brain injury from sports concussions than adults (Neelakantan et al. 2020), which often presents as learning difficulties and cognitive impairment while children are still in school (Lowry et al. 2019).

Cycling, whether as a sport or a mode of transport/recreation, was associated with the largest number of sports concussion hospitalisations (18%) (Figure CON.6). It was also the sport with the most concussion hospitalisations for males (360); for females, this was equestrian activities (150). This difference is similar to that seen in total sports injury hospitalisations (AIHW 2023d). 

It is estimated that 13% of Australians aged over 15 participate in cycling, making it the fifth most popular sport/recreational activity (ASC 2023). This high participation rate, together with cyclists representing 1 in 4 injury hospitalisations from land transport crashes (AIHW 2023e), likely factors into the greater number of cyclist concussions.

Figure CON.6: Cycling was associated with the largest number of sports concussion hospitalisations

When evaluating the incidence of sports-related concussion, it is important to consider the popularity of the sport, or participation rates (AIHW 2023g). Every year, the AusPlay ^TM survey asks a sample of 20,000 Australians about their participation in sports and physical activity (ASC 2023). 

Using these participant estimates for selected sports, those with the highest rates of concussion hospitalisation per 100,000 participants were: 

• equestrian activities (53)
• rugby codes (49) 
• wheeled motor sports (43) (Table CON.1). 

Females have higher rates of concussion across contact sports

The rugby codes (covering both union and league) had the highest rates of concussion for females, with rates 1.6 times higher than for males (72 and 45 per 100,000 participants) (Table CON.1). This is consistent with research indicating that female athletes are more susceptible to concussion than males, and have a greater risk of poorer health outcomes. Factors influencing this may include: 

• physiological differences (such as reduced neck strength)
• recent rapid increase of female participation in contact sports
• greater likelihood of reporting and seeking health services for concussions (AIS and AMA 2016; Di Battista et al. 2019; McGroarty et al. 2020).

Notes

1. Sports are ICD-10-AM activity codes mapped to AusPlay^TM sports categories following convention in Sports Injury in Australia technical notes.
2. Numerator counts are from the National Hospital Morbidity Database.
3. Denominator counts are estimates from the AusPlay ^TM survey. (AusPlay ^TM is a sample survey which may be subject to sampling error.) See Sports Injury in Australia technical notes for more information.

Sources: AIHW National Hospital Morbidity Database; AusPlay ^TM survey results July 2021 – June 2022.

Falls and transport crashes are the leading causes of sports concussion hospitalisations

Similar to all concussion hospitalisations, the 2 leading causes of concussion hospitalisation while participating in sport were falls (36%) and transport (34%). Injuries caused by falls were present in 31 of the 34 sports identified through activity codes. Sports-related hospitalised concussion cases caused by transport mostly occur (94%) in transport-based sports across cycling, wheeled motor sports and equestrian activities.

Looking within cause groups, sports concussion hospitalisations made up most concussions caused by ‘contact with living things’. Nearly three-quarters (73%) of concussions caused by contact with living things involved sport, which can include unintentional person-to-person contact (Figure CON.7). 

Injuries involving a fall because of a collision with or pushing by another person (for example, during a rugby tackle) are included in the numbers of concussions caused by falls, not contact with living things. Of these 480 hospitalisations, 86% involved sport.

Figure CON.7: Sports were involved in the majority of concussions caused by contact with living things

Note: ‘Other causes’ includes Drowning and submersion, Choking and suffocation, Accidental poisoning, Electricity and air pressure, Forces of nature, Overexertion, Other specified and Undetermined intent.

Source: AIHW National Hospital Morbidity Database.

What is the severity of concussions?

There are many ways the severity, or seriousness, of an injury can be measured. Severity metrics in this article compare concussions over time, and against all other head injuries – fractures, for example.

ED triage trends are changing for concussion presentations

Between 2014–15 and 2021–22, the proportion of lower urgency concussion presentations (Semi-urgent or Non-urgent triage) increased (from 29% to 32%), while Urgent presentations fell (54% to 50%). The increase in lower urgency concussion ED presentations could be driven, in part, by increased public awareness of concussion.

Most concussion ED presentations are seen on time

Based on triage waiting time cut-offs, 58% of concussion ED presentations were seen on time (Table CON.2) in 2021–22 – a drop from the peak of 68% seen on time in 2014–15 and 2019–20. Concussions were less likely to be seen on time than all ED presentations, where 67% were seen on time in 2021–22, though this proportion, too, was down, from 74% in 2019–20 (AIHW 2021a, 2023c).

Concussion ED presentations were generally triaged as being more serious than other head injuries (including fractures, open wounds and superficial injuries). The most common triage category for concussions was Urgent (50%), while for other head injuries, it was Semi-urgent (49%).

Source: AIHW National Non-Admitted Patient Emergency Department Care Database.

Fewer concussion cases are being admitted to hospital from ED

From 2019–20 onwards, the proportion of patients being admitted to hospital or transferred to another hospital from an ED fell by 4.3 percentage points, while patients who completed an episode of care and departed without being admitted or referred to another hospital increased by 4.1 percentage points. 

This is the reverse of the trend between 2015–16 and 2019–20, where admissions and referrals increased by 2.8 percentage points, and non-admissions decreased by 3.0 percentage points. (Figure CON.8). This reinforces international research indicating that the COVID-19 pandemic saw a reduction in hospital admissions through EDs (Nourazari et al. 2021; Reschen et al. 2021). 

Figure CON.8: Trends in ED end status are changing, with fewer concussion cases being admitted to hospital

Where to from here?

Monitoring the prevalence of concussions both on and off the sporting field remains a high priority in injury reporting. Under-reporting presents challenges in establishing the true causes, severity and health-care burden associated with concussions.

The AIHW is actively exploring linked data sets to expand the capabilities of injury surveillance beyond initial acute hospitalisations (AIHW 2023f). This approach would be useful in a concussion and sub-concussion context for progressive diseases that accelerate with repeated head injuries. Investigating the relationship between the number of hospitalised concussions, severity of hospitalisation, and recovery pathways would provide insights into the long-term health-care burden of concussions. An AIHW report on traumatic brain injury indicated the usefulness of larger scale applications of this data linkage approach (AIHW 2021b).

Analysing ED external cause data would assist with exploring factors contributing to the increase in ED presentations. External cause data are currently not consistently collected and/or provided by all jurisdictions to the AIHW. Improving collection to align with hospitalisations data would allow for greater analysis of ED injury presentations, which could identify potential avenues for targeted prevention.

The recent Senate inquiry into concussions and repeated head trauma in contact sports (Senate Community Affairs References Committee 2023) recommended that a national sports injury database be set up as a matter of urgency. The AIHW has begun this work, with funding from the Australian Sports Commission. Along with injury data from community sporting organisations, ED external cause data would be an essential part of this data collection.

Further reading

• Economics of sport and physical activity participation and injury (AIHW web report)
• Head injuries in Australia 2020–21 (AIHW web report)
• Health service use for patients with traumatic brain injury (AIHW web report)
• Injury in Australia (AIHW web report)
• Sports injury in Australia (AIHW web report)

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