Asthma

What is asthma?

Asthma is a common chronic condition that affects the airways (the breathing passage that carries air into our lungs). People with asthma experience episodes of wheezing, shortness of breath, coughing, chest tightness and fatigue due to widespread narrowing of the airways (NACA 2022).

The symptoms of asthma are usually reversible. The severity of asthma ranges from mild, intermittent symptoms, causing few problems for the individual, to severe and persistent wheezing and shortness of breath. In people with severe asthma, the disease can have a severe adverse impact on quality of life and may be life-threatening.

It is worth noting that it can be difficult to distinguish asthma from chronic obstructive pulmonary disease (COPD) because the symptoms of both conditions can be similar—both have obstruction to the airways and both are chronic inflammatory diseases that involve the small airways (Cukic et al. 2012). Although the current definitions of asthma and COPD overlap, there are some important features that distinguish typical COPD from typical asthma. For more information, see Chronic obstructive pulmonary disease (COPD).

In addition, clinical symptoms of asthma and bronchiectasis may overlap significantly as symptoms of cough, sputum and dyspnoea can occur in either asthma or bronchiectasis (Kang et al. 2014). Although these two diseases present several common characteristics, they have different clinical outcomes and treatment approaches. Therefore, it is important to differentiate them at early stages of diagnosis, so appropriate management can be provided to achieve better quality of life (Athanazio 2012). Clinical guidelines for managing children with bronchiectasis have recently been updated (Chang et al. 2023).

Monitoring asthma in Australia: The National Asthma Strategy 2018

The National Asthma Strategy (the Strategy) outlines Australia’s national response to asthma and informs how existing limited health care resources can be better coordinated and targeted across all levels of government (NACA 2018). The Strategy also identifies the most effective and appropriate interventions to reduce the impact of asthma in the community.

The National Asthma Indicators

In terms of population-level monitoring, the Strategy includes a set of 10 national asthma indicators designed to provide valuable information for policymakers about the status of asthma in Australia. The National Asthma Indicators – an interactive overview was published in 2019. These indicators have been updated and are included throughout this report where relevant and are also published separately here.

It should be noted that data for recent years may be affected by the COVID-19 pandemic and the range of public health interventions that were put in place to help contain the spread of the virus that causes COVID-19 (for details see Australia’s Health 2022).

What causes asthma?

The fundamental causes of asthma are not completely understood. The strongest risk factors for developing asthma are a combination of genetic predisposition with environmental exposure to inhaled substances and particles that may provoke allergic reactions or irritate the airways. These are often termed asthma triggers and include examples such as:

• viral respiratory infections
• indoor allergens (for example, house dust mites in bedding, carpets, and stuffed furniture, pollution, and pet dander)
• outdoor allergens (such as pollens and moulds)
• tobacco smoke
• chemical irritants, including at the workplace
• air pollution
• strong odours, such as perfume.

Other triggers can include cold air, change in temperature, thunderstorms, extreme emotional arousal such as anger or fear, hormonal changes, pregnancy, and physical exercise. Certain medications can also trigger asthma: aspirin and other non-steroid anti-inflammatory drugs, and beta-blockers (used to treat high blood pressure, heart conditions and migraine) (WHO 2017).

Risk factors associated with asthma

Asthma shares several modifiable risk factors with other chronic conditions, such as:

• tobacco use (smoking or exposure to cigarette smoke)
• exposure to environmental hazards (for example, exposure to air pollutants)
• overweight/obesity
• sedentary lifestyle.

Asthma can also be associated with having other conditions such as allergic rhinitis (Beasley et al. 2015).

Risk factors may increase the chance of developing asthma in the first place (either in childhood or as an adult) or may increase the chance that a person with asthma will develop additional health problems.

Risk factors vary according to the person's age, and according to the type of asthma that they have. Having a risk factor that is associated with asthma, or poor health outcomes related to asthma, does not necessarily mean that the risk factor caused these problems, or that they can be prevented.

In people with asthma, risk factors associated with an increased risk of flare-ups include:

• having frequent episodes of coughing, shortness of breath, and wheezing (e.g., more than 2 days/week)
• not taking preventer treatment regularly (medicines used every day in asthma control to minimise symptoms and reduce the likelihood of episodes or flare-ups. Inhaled corticosteroids are the most used preventers) (NACA 2022)
• frequent reliever inhaler use (medicines used for the rapid relief of asthma symptoms when they occur) (NACA 2022)
• comorbidities (e.g., mental illness, obesity, chronic rhino sinusitis)
• major socioeconomic problems
• exposure to smoking; allergens; air pollution (GINA 2019).

These risk factors may differ depending on the severity of asthma type a person has (McDonald et al. 2018).

Common risk factors

Based on the 2020–21 National Health Survey (NHS), people with asthma were more likely to be current daily smokers, insufficiently physically active and/or obese, compared with those without asthma (see Figure 1). Risk factor definitions are included in the Technical notes section of this report. These risk factors are also common among people with other chronic conditions.

Selected risk factors

Smoking status

Tobacco use or exposure to environmental tobacco smoke are risk factors associated with the development of asthma. For people who already have asthma, smoking or exposure to environmental tobacco smoke can increase the risk of flare-ups and need for emergency care for asthma (Polosa & Thomson 2013). In people with asthma, smoking is also associated with a reduced effectiveness of inhaled corticosteroids (Roche et al. 2015).

And yet, in 2020–21, people with asthma were more likely to be current daily smokers (14%, compared with 10% for people without asthma), and less likely to have never smoked compared with people without asthma (58% and 63%, respectively).

For support to quit, speak to your GP or call the Quitline (13 7848).

Physical activity

Evidence suggests that sedentary behaviour (as measured by screentime engagement) is associated with asthma symptoms in children (Rota et al. 2017). The association between physical activity and asthma symptoms may be complicated by the fact that, in some people who already have asthma, physical activity may trigger asthma symptoms, particularly if their asthma is poorly controlled.

Physical activity is generally recommended for adults and children with asthma to help manage the disease and improve quality of life (NACA 2022). Further, greater levels of physical activity and participation in rehabilitation programs is associated with improved asthma outcomes (Freitas 2021).

Based on the 2020–21 NHS, people with asthma were slightly less likely than people without asthma to meet the 2014 physical activity guidelines (24% compared with 28% for people without asthma).

Body mass

Studies show there are associations between overweight and obesity, as measured by Body Mass Index (BMI), and asthma, especially in high income countries (Beasley et al. 2015). Additionally, people with asthma who are overweight or obese often experience complications in treatment. There is evidence of an association between being obese and developing asthma; however, the causative mechanisms between body mass and asthma are not currently well understood (Peters et al. 2018; Kim et al. 2014).

Based on the 2020–21 NHS, people with asthma were 1.8 times as likely to be obese (by self-reported body mass index or BMI—see Technical notes) as people without asthma (39% and 22% respectively). Note that self-reported data is likely to an underestimate.

The following dashboard can be used to explore the data in more detail.

Figure 1: Prevalence of selected risk factors in people aged 18 and over with and without asthma, 2020–21

Age differences in risk factors in people with asthma

For people with asthma, the prevalence of risk factors varies by age. In 2020–21, people aged 18–44 and 45–64 with asthma were more likely to be a current daily smoker (14% and 16%, respectively) compared with those aged 65 and over (9.4%) (Figure 2). Smoke free laws, tobacco price increases, plain cigarette packaging and greater exposure to mass media campaigns may contribute to lower smoking rates among older Australians (Wakefield et al. 2014).

People with asthma aged 45–64 were more likely to be a current daily smoker, not to meet the 2014 physical activity guidelines and to be obese compared with those aged 18–44 and those aged 65 and over.

The following dashboard can be used to explore the data in more detail.

Figure 2: Prevalence of selected risk factors in people aged 18 and over with asthma, by age group, 2020–21

How common is asthma?

Around 2.7 million Australians (11% of the population) have asthma, based on self‑reported data from the 2020–21 Australian Bureau of Statistics (ABS) National Health Survey (NHS) (ABS 2022a).

Prevalence by age and sex

Based on the 2020–21 NHS, among those aged 0–14, asthma rates were similar for boys (9.3%) and girls (7.7%). Over the age of 15, asthma was more common among women for all age groups except those aged 25–34. Prevalence was the same (10%) for males and females for those aged 25–34 (Figure 3).

This change in prevalence for males and females in adulthood is likely due to a complex interaction between changing airway size and hormonal changes that occur during adolescent development, as well as differences in environmental exposures (Dharmage et al. 2019).

Prevalence in Aboriginal and Torres Strait Islander people

In 2018–19, 18% of Aboriginal and Torres Strait Islander people (about 128,000) reported having asthma, with a higher rate among females (18%) compared with males (13%). Rates were similar to those reported in 2012–13 (19%) (ABS 2019).

The prevalence of asthma among Indigenous Australians was 1.6 times as high as non-Indigenous Australians (18% and 11%, respectively) after adjusting for differences in age structure (Figure 3). The difference in asthma prevalence between Indigenous and non-Indigenous Australians exists across all age groups but is more marked for older adults.

For more information and data on respiratory conditions in Aboriginal and Torres Strait Islander people, see the Aboriginal and Torres Strait Islander Health Performance Framework Measure 1.04 (1.04 Respiratory disease – AIHW Indigenous HPF).

The following dashboard can be used to explore the data in more detail.

Figure 3: Prevalence of asthma, by sex, age and Indigenous status

Variation between population groups

Based on the 2020–21 NHS, people born in Australia were more than twice as likely as those born overseas to have asthma (13% compared with 6%) (ABS 2022a).

Those who live in Inner regional areas were more likely than those who live in Outer Regional and Remote areas to have asthma (13% compared with 9%) (ABS 2022a).

People with a profound or severe core activity limitation were almost 3 times more likely than those with no disability to have asthma (23% compared with 8%) (ABS 2022a).

Additional data on asthma prevalence by country of birth and other culturally and linguistically diverse measures are also reported using the ABS 2021 Census in Chronic health conditions among culturally and linguistically diverse Australians, 2021 (AIHW 2021b).

Impact of asthma

Asthma has varying degrees of impact on the physical, psychological, and social wellbeing of people living with the condition, depending on disease severity and the level of control. People with asthma are more likely to report poor quality of life, especially those with severe or poorly controlled asthma (ACAM 2011).

Burden of disease

In 2022, asthma accounted for 2.5% of total disease burden (DALY); 4.5% of non-fatal burden (YLD), and 0.3% of fatal burden (YLL). Within the respiratory disease group, asthma accounted for 34% of total burden (DALY); 52% of non-fatal burden (YLD); and 5.4% of fatal burden (YLL).

Variation by age and sex

• Overall, the total burden from asthma for females was 1.2 times as high as for males (5.6 vs 4.9 DALY per 1,000 population).
• Asthma was the leading cause of burden for people aged 1–4, 5–9, and 10–14 years (11.1%, 14.5%, and 12.0% of total burden (DALY), respectively).
• Young males (aged under 20) had a substantially higher rate of asthma burden (DALY) than young females. This difference was especially pronounced for those aged 1–14, where the male rate was more than 40% higher than the female rate.

The following dashboard can be used to explore the indicator data in more detail.

Figure 4: Burden of disease due to asthma, by sex, age and year

Trends over time

The rate of asthma burden increased from 4.9 to 5.3 DALY per 1,000 population between 2003 and 2022 or 0.4% per year on average, after adjusting for changes in age structure. This increase was driven by non-fatal burden (YLD).

Further detail is available in the Australian Burden of Disease Study 2022.

Variation between population groups

In 2018, after adjusting for age, rates of asthma burden (DALY, YLL and YLD) increased with increasing remoteness and levels of disadvantage:

• Remote and very remote areas were 1.5 times as high as Major cities (7.3 and 5.0 DALY per 1,000 population, respectively).
• Fatal burden (YLL) had the greatest contrast between socioeconomic group. The lowest socioeconomic group (living in the areas with the highest level of disadvantage) had around 6 times the rate of fatal burden for asthma than the highest group (living in areas with the lowest level of disadvantage) (AIHW 2021a).

Further detail is available in the Australian Burden of Disease Study 2018: Interactive data on disease burden.

The following dashboard can be used to explore the indicator data in more detail.

Figure 5: Burden of disease due to asthma, by sex, remoteness area, socioeconomic group and year

Health system expenditure

Understanding the contribution of asthma to direct health care expenditure helps to explain the economic impact of the disease. Furthermore, knowledge of the relative contribution of the various health care sectors (hospital, out-of-hospital medical care, and pharmaceutical) to overall asthma-related expenditure assists in planning interventions to optimise this expenditure.

It should also be acknowledged that financial costs represent a small part of the overall economic impact caused by asthma. A report on the estimated economic cost of asthma in Australia was published in 2015 and data included in the 2018 National Asthma Strategy (Deloitte 2015; NACA 2018).

In 2019–20, an estimated $899.9 million of expenditure in the Australian health system was for asthma, representing 0.6% of total health expenditure and 19% of expenditure of all respiratory conditions (AIHW 2022c).

Where is the money spent?

Figure 6 presents a detailed breakdown of estimated expenditure for asthma by area of the health system, showing that:

• Primary care represented 71% ($639.1 million) of asthma expenditure, which was around 2.5 times the primary care portion of total health expenditure (28%). The Pharmaceutical benefits scheme proportion of asthma expenditure was especially large in comparison to the average, more than 4 times the proportion for total health expenditure (51% compared with 12%).
• Hospital services accounted for 24% ($219.1 million) of asthma spending, which was around 2.6 times lower when compared with the proportion of total health expenditure for hospital services (63%). The public hospital emergency department proportion of asthma expenditure was especially large in comparison to the average, 1.6 times the proportion for total health expenditure (7.5% compared with 4.7%).

• Referred medical services represented 4.6% ($41.6 million) of asthma expenditure, which was less than the proportion of total health expenditure for referred medical services (9.1%).

The following dashboard can be used to explore the data in more detail.

Figure 6: Amount and proportion (%) of asthma expenditure attributed to each area of the health system, compared to expenditure for all disease groups, 2019–20

Figure 7 presents the component (%) that asthma expenditure makes up for each area of the health system, showing that in 2019–20, asthma accounted for:

• 2.6% ($455.0 million) of all Pharmaceutical benefits scheme expenditure – ranking 9th of all diseases/conditions.
• 0.2% ($84.1 million) of all public hospital admitted patient expenditure.

The following dashboard can be used to explore the indicator data in more detail.

Figure 7: Proportion of expenditure attributed to asthma, for each area of the health system, 2019–20

Who is the money spent on?

In 2019–20:

• The age distribution of spending on asthma reflects the prevalence distribution, with the majority being spent on older age groups (52% for people aged 45 and over).
• More asthma expenditure was attributed to females than males ($494.9 million and $354.1 million, respectively), with the remainder $50.9 million (5.7%) not specified.

Further detail is available in Disease expenditure in Australia 2019–20.

In 2018–19, it was estimated that:

• Asthma expenditure per case was 1.1 times greater for females than males ($290 and $265 per case, respectively).
• Asthma expenditure per case was 44% lower than respiratory conditions as a group ($285 and $515 per case, respectively) (AIHW 2022d).

Further detail is available in Health system spending per case of disease and for certain risk factors.

Investment in asthma research

Between 2000 and 2022, the National Health and Medical Research Council (NHMRC) has expended $348 million towards research relevant to asthma.

Since its inception in 2015 and 31 March 2023, the Medical Research Future Fund (MRFF) has invested $283.8 million in 151 grants with a focus on respiratory health research. Of these, 8 grants ($11.3 million) focus on asthma research. Examples include:

• $2.4 million to the University of Newcastle for the project titled, A comprehensive digital solution to empower asthma and comorbidity self-management; and
• $1.6 million to the Queensland University of Technology for the project titled, Oral bacterial lysate to prevent persistent wheeze in infants after severe bronchiolitis; a randomised placebo-controlled trial (BLIPA; Bacterial Lysate in Preventing Asthma).

How does asthma affect quality of life?

In 2020–21, self-assessed health status among people with asthma aged 18 and over was, on average, worse than among those without asthma. People with asthma were less likely to describe themselves as having excellent health compared with people without asthma (11% and 21%, respectively), and more likely to describe themselves as having fair health compared with people without asthma (17% and 10%, respectively) (Figure 8). Conversely, people with asthma were more likely to describe themselves as having poor health compared with people without asthma (5.4% and 2.6%, respectively).

During the same period, people with asthma were more likely to experience high and very high levels of psychological distress (19% and 11%, respectively) compared with those without asthma (12% and 6.8%, respectively) (Figure 8).

Just over a fifth of people with asthma (21%) reported that asthma interfered with their daily activities 2 or more times in the past 4 weeks. Eight per cent of people reported interference once (daily activities included going to school, playing with friends, going to work, exercising, and getting around places) (Figure 8).

The following dashboard can be used to explore the data in more detail.

Figure 8: Quality of life measures (age standardised) for people aged 18 and over with and without asthma, 2020–21

Deaths

How many deaths were associated with asthma?

Asthma was recorded as an underlying cause of death for 351 deaths or 1.4 deaths per 100,000 population in Australia in 2021, representing 0.2% of all deaths and 2.6% of all respiratory deaths.

Asthma was recorded as an associated cause of death for an additional 1,641 deaths equalling a total of 1,992 deaths in Australian due to or associated with asthma. This represented 1.2% of all deaths and 4.3% of respiratory deaths.

Variation by age and sex

In 2021, asthma mortality (as the underlying cause of death) was:

• more common in older people (63% aged 75 and over), which is slightly less than the proportion of people aged 75 and over for total deaths (67%).
• higher for females (70% of asthma deaths were female compared with 48% of total deaths).
• similar by age and sex for asthma as the underlying cause of death and any cause of death.

The following dashboard can be used to explore the data in more detail.

Figure 9: Age profile of asthma mortality statistics, by sex

Trends over time

Age standardised mortality rates for asthma (as the underlying cause of death) between 2011 and 2021:

• have slightly decreased with some minor fluctuation between 1.5 and 1.1 per 100,000 population. This trend is reversed when looking at asthma as any cause of death where the rate increased from 5.1 to 6.0 per 100,000 population.
• show that females have had a consistently higher mortality rate than males across all years and this pattern remains true for asthma as an underlying or associated cause of death.

The following dashboard can be used to explore the data in more detail.

Figure 10: Historical asthma mortality statistics, by sex, 2011–2021

Variation between population groups

Remote and very remote areas had less than 20 deaths due to asthma in 2021. Major cities had the least asthma deaths per population compared with Inner regional and Outer regional areas (1.3 and 1.5 times more than Major cities, respectively). There was no difference between remoteness areas when asthma was an associated cause of death only.

The lowest socioeconomic group (living in the areas with the highest level of disadvantage) had 2.3 times more asthma deaths per population than the highest socioeconomic group (living in areas with the lowest level of disadvantage) in 2021 (1.4 vs 0.6 underlying causes of death per 100,000 population, age standardised). The same pattern was seen regardless of whether asthma was recorded as an underlying or associated cause of death.

Aboriginal and Torres Strait Islander people experience higher asthma mortality rates than non-Indigenous Australians:

• In the 5-year period from 2015–2019, 74 Aboriginal and Torres Strait Islander people died from asthma, with a mortality rate of 2.1 per 100,000 population (based on 5 jurisdictions with adequate Indigenous identification (NSW, Qld, WA, SA and NT) (AIHW 2023).
• After adjusting for differences in age structure, the mortality rate of asthma among Indigenous Australians was 2.5 times as high as non-Indigenous Australians (3.7 compared with 1.5 per 100,000 population).

The asthma mortality rate differences between these population subgroups may be due to differences in smoking rates, access to health services, or other social and environmental factors. In Australia, smoking prevalance is higher among people living in more remote areas, among people living in areas of higher disadvantage, and among Indigenous Australians (AIHW 2018).

Further detail on mortality data is available in the Chronic respiratory condition mortality data tables 2023.

Treatment and management of asthma

In general, symptoms of asthma are easily controlled in most people by making lifestyle changes and using medications, so they can have normal lives. The main aims of asthma treatments are:

• to stop asthma from interfering with school, work, or play
• to prevent flare-ups or ‘attacks’
• to keep symptoms under control
• to keep lungs as healthy as possible (NACA 2022).

What medicines are used to treat asthma?

There are several medicines available to treat asthma. Different asthma medicines are used to achieve different goals, as follows:

• Relievers are medicines used for the rapid relief of asthma symptoms when they occur. They can also be used before exercise to prevent exercise-induced bronchoconstriction (constriction of the airways). Short-acting beta agonist medications (SABA) are the most used relievers (NACA 2022).
• Preventers are medicines used every day in asthma control to minimise symptoms and reduce the likelihood of episodes or flare-ups. Inhaled corticosteroids are the most used preventers.
• Other medicines such as long-acting bronchodilators and biologics are used for management of difficult-to-treat asthma or as add-on options for management of severe asthma flare-ups.

Treatment guidelines for asthma for people aged 12 and older changed in 2020 i.e. the suggested prescription is now a single inhaler with inhaled corticosteroids (ICS) and a long-acting muscarinic antagonist (LAMA), specifically budesonide/formoterol (Symbicort) used as both a preventer and reliever (Reddel 2020)

A relatively new class of medications known as biologics are also being increasingly prescribed to those with severe asthma. Biologics act like preventers but are not classified as such. They can only be prescribed by a respiratory specialist and some are not yet covered by the Pharmaceutical benefits scheme (PBS). Therefore, not all biologics are included in reporting on medications in this section.

A key focus of the National Asthma Strategy is to improve outcomes for those with severe or poorly controlled asthma (NACA 2018). Asthma is described as well-controlled when there are few symptoms and little reliever use (e.g., less than 2 days/week), and no night waking or limitation of activity. ‘Well-controlled asthma’ may indicate mild disease and/or good management, whereas ‘poorly-controlled asthma’ may indicate severe disease or poor management.

Assessing the overall level of asthma control in the population can provide insight into the effectiveness of the management of asthma in the community and the need for further efforts in improving asthma management.

Frequent use of relievers is an indicator of poor asthma control, with dispensing frequency used as a proxy for reliever use:

• 3 or more reliever prescriptions per year indicating poor asthma control
• 6 or more indicating very poor control
• 12 or more indicating extremely poor asthma control (ACAM 2011).

In line with guidance from the AIHW’s National Asthma and Other Chronic Respiratory Conditions Monitoring Advisory Group, the dispensing of reliever medicines 3 or more times in 12 months has been selected as the threshold for poor asthma control.

Analysis of 2021–22 Pharmaceutical benefits scheme (PBS) data shows that, of all people aged 40 and under who were dispensed at least one reliever, 18% were dispensed relievers 3 or more times within 12 months (Figure 11).

Variation by age and sex

• The rate of dispensing relievers 3 or more times in 12 months was the same (18%) for men and women for all ages (0–40) however increased with age.
• Twenty-six per cent of people aged 35–40 dispensed at least one reliever were dispensed relievers 3 or more times in 12 months – higher than for all other age groups.

Trends over time

Rates have changed little since 2017–18 but for all age groups apart from 0–14, a spike can be seen in 2020–21 (Figure 8). The corresponding spike for those aged 0–14 is observed earlier, in 2019–20. This same trend is noted for preventer medications (Indicator 6) and may be related to anecdotal evidence that many people started to panic buy respiratory medication in 2020 during the COVID-19 pandemic where they had an existing condition. Bushfires in 2019–20 may also have contributed to this increase in dispensing of asthma medication.

From the end of March 2020 pharmacists were strongly encouraged to limit dispensing and sales of all therapeutic goods (especially salbutamol inhalers) generally to a one-month supply or one unit in response to the stockpiling occurring (DoHAC:TGA 2020). In October 2020, changes in legislation were enacted to limit dispensing of some asthma medication (mainly salbutamol) to a maximum of one pack per person (PSA 2022).

The following dashboard can be used to explore the data in more detail.

Figure 11: Proportion of people aged 40 and under dispensed at least one reliever, who were dispensed relievers 3 or more times within 12 months, by sex and age, 2017–18 to 2021–22

Preventer medicine is the mainstay of asthma management, to minimise symptoms and exacerbations. National guidelines for the management of asthma recommend preventers to be taken regularly (either daily or twice daily) rather than intermittently (NACA 2022).

In line with advice from the AIHW’s National Asthma and Other Chronic Respiratory Conditions Monitoring Advisory Group, the dispensing of these medicines 3 or more times in 12 months has been selected as the threshold for reflecting better management of moderate to severe asthma.

Analysis of 2021–22 Pharmaceutical Benefits Scheme (PBS) data shows that, of people aged 50 and under who were dispensed at least one preventer medicine, 33% were dispensed preventer medicines 3 or more times within 12 months.

Variation by age and sex

• The rate of dispensing preventers 3 or more times in 12 months was slightly higher for males than females (35% and 31%, respectively).
• Males dispensed at least one preventer had higher rates of being dispensed preventers 3 or more times in 12 months compared with females irrespective of age (Figure 12).
• Children aged 0–14 were dispensed preventers at a similar rate to people aged 25–34 (29% and 30%).
• Slightly fewer people aged 15–24 (25%) were dispensed preventers 3 or more times in 12 months, the lowest rate for all people aged 50 and under.
• The rate of dispensing preventers 3 or more times in 12 months increased with age from 25% for those aged 15–24, up to 41% for those aged 45–50.

Trends over time

Rates have changed little since 2017–18 but for all age groups apart from 0–14, a spike can be seen in 2020–21 (Figure 9). The corresponding spike for those aged 0–14 is observed earlier, in 2019–20. This same trend is noted for asthma control medications (Indicator 5), and as covered in detail in that section, may be due to stockpiling of medication during the COVID-19 pandemic and a subsequent restriction in dispensing of some medications to combat this. Bushfires in 2019–20 may also have contributed to this increase in dispensing of asthma medication.

Further information on the specific preventer medication that this indicator covers is provided in the Technical specifications for this report. 

For more detailed information about medicines used to treat asthma and the national guidelines for asthma management, refer to Australian Asthma Handbook, Version 2.2.

The following dashboard can be used to explore the data in more detail.

Figure 12: Proportion of people aged 50 and under dispensed at least one preventer medicine, who were dispensed preventer medicines 3 or more times within 12 months, by sex and age, 2017–18 to 2021–22

Management of asthma

Since asthma is a chronic disease, it requires management all the time, not just when symptoms are present. The four parts of managing asthma are:

• identify and minimise exposure to asthma triggers
• understand and use medications as prescribed to have good asthma control
• monitor asthma to recognise signs when it is getting worse
• know what to do when asthma gets worse (Stanford Children’s Health 2020).

For more detailed information about management of asthma, refer to the Australian Asthma Handbook, Version 2.2: Management for children, adolescents, and adults.

What role do GPs play in managing asthma?

General practitioners (GPs) play an important role in the management of asthma in the community. This role includes assessment, diagnosis, prescription of regular medications, education, provision of written action plans, and regular review as well as managing asthma flare-ups. Asthma-related visits to GPs may occur for a variety of reasons, including:

• the acute or reactive management of asthma symptoms
• a review during or following a flare-up
• a review or initiation of a written action plan
• a visit for maintenance activities, such as monitoring and prescription of regular medications
• review asthma with other possible comorbidities
• referral to a specialist and other health professionals.

Until 2017, the Bettering the Evaluation and Care of Health (BEACH) survey was the most detailed source of data about general practice activity in Australia (Britt et al. 2016). In the decade up to 2015–16, according to this survey:

• asthma was one of the most frequently managed chronic problems
• the estimated rate of asthma management in general practice declined from 2.3 in 100 encounters to 2.0 in 100 encounters.

It is worth noting that there is currently no nationally consistent primary health care data collection to monitor provision of care by GPs. See General practice, allied health and other primary care services.

Asthma cycle of care

Asthma cycle of care claims are used as a proxy for GP care for asthma since no other data source is available. It involves at least 2 asthma-related consultations with a GP within 12 months for a patient with moderate-to-severe asthma. There are 12 MBS items for GP consultations that relate to the completion of an asthma cycle of care.

Asthma cycle of care data has been included for this update but it should noted that these items were removed from the Medicare Benefits Scheme as of 1 November 2022 and thus will not be used for reporting on GP encounters for asthma in future (RACGP 2022).

Data development work is being progressed to identify a suitable alternative to this data.

Limitations of the asthma cycle of care data include that:

• patients may also use other forms of health care to manage their asthma, which are not covered by this cycle of care measure.
• the denominator for this indicator includes all people in Australia not just those diagnosed with asthma.

Analysis of Medicare Benefits Schedule (MBS) data shows that 0.1% of the population (around 13,000 people) claimed the completion of the asthma cycle of care in 2021–22, with little difference observed by sex after adjusting for age structure (Figure 13). 

From 2017–18 to 2021–22, the proportion of people claiming the asthma cycle of care decreased from 0.3% to 0.1%. This decrease was noted for all age groups and was slightly greater for females than males (0.3% to 0.1% and 0.2% to 0.1%, respectively).

The following dashboard can be used to explore the data in more detail.

Figure 13: Proportion of people who claimed the completion of the asthma cycle of care service, by age and sex, 2017–18 to 2021–22

Asthma action plans

An asthma action plan is a written self-management plan which is prepared for patients with asthma by a health care professional to help them manage their condition and reduce the severity of acute asthma flare-ups. A patient’s individualised plan is developed to deal with their personal triggers, signs and symptoms, and medication.

Asthma action plans have formed part of the National Asthma Council Australia's guidelines for the management of asthma for over 30 years (NAC 1990) and have been promoted in public education campaigns on the basis that individualised written action plans improve asthma health outcomes (NACA 2022).

According to the 2020–21 NHS, an estimated 34% of people with self-reported asthma across all ages had a written asthma action plan.

Variation by age and sex

• over two-thirds (69%) of children under 14 years of age had a written action plan, while less than one quarter (23%) of people aged 75 and over had a written action plan (ABS 2022a).
• Across all ages, females were more likely than males to have a written asthma action plan.

It is likely that these differences by age are due to schools and child care facilities requiring that children with asthma have a health care provider issued asthma action plan (Asthma Australia 2022).

Variation between population groups

Thirty-two per cent of Indigenous Australians had a written asthma action plan in 2018–19, with those living in Non-remote areas more likely to have a plan compared with those living in Remote areas (32% compared with 27%) (Figure 14).

The following dashboard can be used to explore the data in more detail.

Figure 14: Proportion of people with asthma who have a written asthma action plan by age, by age and sex, and for Indigenous Australians by remoteness area, 2020–21

What role do hospitals play in treating asthma?

People with asthma require admission to hospital when flare ups or ‘attacks’ are potentially life-threatening or when they cannot be managed at home or by a GP.

Data from the AIHW National Hospital Morbidity Database (NHMD) show that in 2020–21, there were 25,000 hospitalisations where asthma was the principal diagnosis. The age-standardised rate of hospitalisations for asthma was 100 per 100,000 population.

Variation by age and sex

• The rate among children aged 0–14 (225 per 100,000 population) was markedly higher than the rate among people aged 15 and over (68 per 100,000 population) (Figure 15).
• In 2020–21, boys aged 0–14 were 1.6 times as likely as girls of the same age to be admitted to hospital for asthma.
• Conversely, of those aged 15 and over, females were 2.3 times as likely as males to be admitted to hospital for asthma.

These differences in hospitalisation by sex and age reflect in part the difference in the prevalence of asthma—which tends to be more common in boys than girls for those aged under 15, and generally more common in females than in males for those aged over 25.

Trends over time

During the last decade:

• the rate of hospitalisations where asthma was the principal diagnosis for children aged 0–14 decreased overall, falling from 505 per 100,000 population in 2010–11 to 225 per 100,000 population in 2020–21
• the proportion of children hospitalised overnight decreased from 79 to 64% with an average length of overnight stays of 1.5 days in 2020–21
• the rate of hospitalisations for asthma for those aged 15 and over fluctuated between 92 per 100,000 in 2010–11 and 68 per 100,000 population in 2020–21, peaking at 115 separations per 100,000 in 2016–17
• the proportion of overnight stays also decreased from 78 to 64%, with overnight stays averaging 2.4 bed days in 2020–21 (Figure 15).

The rate of hospitalisations over the past few years have been affected by the COVID-19 pandemic, for more information on this, see the Chronic respiratory conditions COVID-19 impact section.

The following dashboard can be used to explore the data in more detail.

Figure 15: Age profile of asthma hospitalisation statistics, by sex

Age profile of hospitalisations for asthma compared with hospitalisations for all causes

While most hospitalisations for all causes in 2020–21 were for older people, 43% of the 25,000 hospitalisations for a primary diagnosis of asthma in Australia were for children aged 0–14 (Figure 16). The age profile of hospitalisations for asthma was much younger compared with hospitalisations for all causes in the same year.

The following dashboard can be used to explore the data in more detail.

Figure 16: Historical asthma hospitalisation statistics, by sex, 2011–2021

Seasonal variation in hospitalisations for asthma

Among children, the peaks for asthma hospitalisations occur in late summer (February) and autumn (May) (Figure 17). The peak in February is likely related to respiratory infections associated with returns to school and childcare after the summer break. Similar peaks are observed in September in Northern Hemisphere countries; lower use of preventer medication during holidays may also contribute.

Among adults, hospitalisations for asthma are highest in winter and early spring (June through to September), particularly in people aged 65 years and older (Figure 17). This coincides with the annual winter ‘flu’ season and may reflect the rise in respiratory infections observed then.

2020 was an exception to this general trend, and there was a large dip in hospitalisations in April and May for all age groups. This is likely due to lockdown mandates across the nation related to COVID-19. For more on the impact of COVID-19 see the Chronic respiratory conditions COVID-19 impact section.

Asthma hospitalisations can also be impacted by one-off natural events which occur on a seasonal basis, such as thunderstorms and bushfires (See section on ‘Impact of natural events on asthma’ in ‘What causes asthma section’ for more details).

The following dashboard can be used to explore the data in more detail.

Figure 17: Monthly variation in hospitalisations due to asthma, by age group, 2020

Hospitalisations by Primary Health Care Network

In 2020–21, the 3 PHN areas with the highest (age-standardised) rates of hospitalisations were: Western Queensland (QLD), Northern Territory (NT), and Darling Downs and West Moreton (QLD) (245, 200 and 170 per 100,000 population, respectively) (Figure 18).

The 3 PHN areas with the lowest hospitalisation rates were: Perth North (WA), Perth South (WA), and South Eastern NSW (NSW) (54, 54, and 59 per 100,000 population, respectively).

The following dashboard can be used to explore the data in more detail.

Figure 18: Hospitalisations for asthma per 100,000 population by Primary Health Network areas, age standardised rate, 2020–21

Emergency department presentations for asthma

Data from the National Non-Admitted Patient Emergency Department Care Database (NAPEDC) show that in 2020–21, there were 56,600 emergency department (ED) presentations for asthma, about 230 presentations per 100,000 population.

Variation by age and sex

• In 2020–21, rates were higher for females than males overall (245 compared with 215 per 100,000 population).
• However, boys aged 0–14 were 1.6 times as likely as girls of the same age to present to the emergency department for asthma (Figure 19).

Trends over time

Between 2018–19 and 2020–21, ED presentation rates decreased from 297 to 232 per 100,000 population and were higher for females than males (Figure 19).

Seasonal variation was also noted for asthma ED presentation rates though this has been impacted by the COVID-19 pandemic since March 2020 (for COVID-19 pandemic timelines see ABS 2021).

• In 2019, rates were relatively high between March and August (24 to 29 per 100,000 population per month).
• From March to May 2020 ED presentation rates more than halved (from 26 per 100,000 to 11 per 100,000 population). This decrease is likely due to the nationwide lockdown which began on 23 March related to the COVID-19 pandemic.
• ED presentations rose slightly from May 2020, when COVID-19 restrictions began to ease (Figure 19).

Variation between population groups

In 2020–21, the highest rate of ED presentations was reported for people living in Remote areas (430 per 100,000 population), and the lowest was reported for those living in Major cities (200 per 100,000 population) (Figure 19).

ED presentation rates were higher in the lowest socioeconomic group (living in the areas with the highest level of disadvantage) compared with the highest socioeconomic group (living in areas with the lowest level of disadvantage) in 2020–21 (305 compared with 145 per 100,000 population).

The following dashboard can be used to explore the data in more detail.

Figure 19: Emergency department presentations due to asthma, by sex and age, remoteness area and socioeconomic group, by month, 2018–19 to 2020–21

Comorbidities of asthma

Some people with asthma have other chronic and long-term conditions. This is called ‘comorbidity’, which describes any additional disease that is experienced by a person with a disease of interest (the index disease). For people with asthma, having a comorbid chronic condition can have important implications for their health outcomes, quality of life and treatment choices.

Number of comorbid chronic conditions in people with asthma

In 2020–21, around 1.2 million people aged 45 and over, who currently have asthma, also reported having one or more of the following selected chronic conditions:

• arthritis
• back problems
• cancer
• chronic obstructive pulmonary disease (COPD)
• diabetes
• heart, stroke, and vascular disease
• kidney disease
• mental and behavioural conditions
• osteoporosis.

Just under a third (30%) had one other selected chronic condition, and 47% had 2 or more other selected chronic conditions (Figure 20).

These 9 chronic conditions have been selected because they are common in the general community, pose significant health problems, have been the focus of ongoing national surveillance efforts, and action can be taken to prevent their occurrence (ABS 2022b). See the National Health Survey: First Results methodology 2020–21 (ABS 2022c) for more information.

Asthma affects people of all ages; however, many of the people with asthma and comorbid conditions are older Australians, reflecting the fact that chronic conditions are more widespread in older age groups (AIHW 2022a).

Additional chronic conditions that are commonly found in people with asthma, and that can impact on asthma, include allergic rhinitis, obstructive sleep apnoea, mental illness, nasal polyps (soft, painless, non-cancerous growths) and gastro-oesophageal reflux disease (GORD) (Bardin et al. 2018; Cazzola et al. 2012).

Types of self-reported comorbid chronic conditions in people with asthma

Among people aged 45 and over with asthma:

• 42% had arthritis (compared with 26% among people without asthma)
• 33% had back problems (compared with 23% among people without asthma)
• 20% had mental and behavioural conditions (compared with 11% among people without asthma)
• 14% had COPD (compared with 1.9% among people without asthma)
• 31% had heart, stroke, and vascular disease (compared with 22% among people without asthma)
• 13% had osteoporosis (compared with 7.6% among people without asthma) (Figure 20).

The following dashboard can be used to explore the data in more detail.

Figure 20: Comorbidity and prevalence of selected chronic conditions in people aged 45 and over with and without asthma, 2020–21