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).

It is worth noting that while asthma shares similar symptoms and can co-occur or overlap with other respiratory conditions such as Chronic obstructive pulmonary disease (COPD) and Bronchiectasis, it remains a distinct condition for diagnosis and treatment. 

The National Asthma Indicators

In 2018, the National Asthma Strategy was released, outlining Australia’s national response to asthma. It includes 10 national asthma indicators designed to provide valuable information for policymakers about the status of asthma in Australia (NACA 2018).

The National asthma indicators report was first published in 2019 and is updated regularly. Detailed information and data on these indicators are also included throughout the asthma web pages.

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. 

Asthma triggers can include viral respiratory infections, allergens (indoor or outdoor), tobacco smoke and air pollution, chemical irritants, including in the workplace and strong odours, such as perfume.

Certain medications can also trigger asthma, such as: 

• aspirin and other non-steroid anti-inflammatory drugs
• beta-blockers (used to treat high blood pressure, heart conditions and migraine) (WHO 2017).

Natural disasters or extreme weather changes can affect human health drastically, and events that affect air quality can have a direct impact on asthma. Two natural events that have affected asthma in recent times are thunderstorm asthma and the bushfires of 2019–20. 

How common is asthma?

Around 2.8 million (11%) people in Australia were estimated to be living with asthma, according to self reported data in the 2022 Australian Bureau of Statistics (ABS) National Health Survey (NHS) (ABS 2023). 

In 2022, the prevalence of asthma was:

• higher for boys compared with girls aged 0–14 (10% and 6.2%, respectively)
• higher for females compared with males over the age of 15 (Figure 1) (ABS 2023).

This change in prevalence for males and females over the age of 15 is likely to be 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).

After adjusting for different population age structures over time, the prevalence of asthma has remained relatively stable, at 12% in 2001 and 11% in 2022 (Figure 1) (ABS 2023).

Based on the 2022 NHS, there was little difference in the prevalence of asthma by remoteness area or level of disadvantage (also known as socioeconomic area) (Figure 1) (ABS 2023).

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).

Figure 1: Prevalence of asthma, by age and sex, over time (2001 to 2022), by population group, 2022

Prevalence in Aboriginal and Torres Strait Islander (First Nations) people

The Australian Institute of Health and Welfare (AIHW) uses ‘First Nations people’ to refer to Aboriginal and/or Torres Strait Islander people in this report. 

In 2018–19, around 128,000 (16%) First Nations people were estimated to be living with asthma, based on the National Aboriginal and Torres Strait Islander Health survey (NATSIHS) (Figure 2), down from 18% in 2012–13 (ABS 2019). 

For more information, see First Nations people with asthma. 

For more information about First Nations people with respiratory conditions, see Aboriginal and Torres Strait Islander Health Performance Framework Measure 1.04 (AIHW 2023a).

Figure 2: Prevalence of asthma, by Indigenous status, sex and age, 2018–19

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 their level of control. People with asthma are more likely to report poor quality of life, especially those with severe asthma (Kharaba et al. 2022).

Measures of impact presented in this section include burden of disease, health expenditure and mortality data.

Burden of disease

In 2023, asthma accounted for 2.5% of total disease burden (also known as disability adjusted life years or DALY), 4.4% of non-fatal burden (also known as ‘years lived with disability’ or YLD) and 0.3% of fatal burden (also known as years of life lost, or YLL). 

Within the respiratory disease group, asthma accounted for:

• 35% of total burden (DALY)
• 52% of non-fatal burden (YLD) 
• 5.4% of fatal burden (YLL) (AIHW 2023b).

Variation by age and sex

In 2023:

• the overall rate of burden from asthma was 1.2 times as high for females compared with males (5.8 and 4.9 DALY per 1,000 population, respectively)
• asthma was the leading cause of burden for children aged 1–4 and 5–9 years (11%, and 13% of total burden (DALY), respectively) (Figure 3).

Figure 3: Burden of disease due to asthma, by sex and age, 2003, 2011, 2015, 2018 and 2023

Trends over time

After adjusting for different population age structures over time, the rate of asthma burden increased by 8% (from 4.9 to 5.3 DALY per 1,000 population, respectively) – or 0.4% per year on average between 2003 and 2023. This increase was driven by non-fatal burden (YLD).

For more information, see the Australian Burden of Disease Study 2023.

Variation between population groups

In 2018, after adjusting for age differences, the rate of burden from asthma was highest for people living in:

• Remote and very remote areas and lowest for people living in Major cities (7.3 and 5.0 DALY per 1,000 population, respectively)
• areas of most disadvantage (lowest socioeconomic areas) and lowest for people living in the least disadvantaged areas (highest socioeconomic areas) (6.9 and 3.7 DALY per 1,000 population, respectively) (Figure 4) (AIHW 2021c).

For more information, see the Australian Burden of Disease Study 2018: Interactive data on disease burden.

Figure 4: Burden of disease due to asthma for remoteness area and socioeconomic area, by sex, 2011, 2015 and 2018

Health system expenditure

Understanding the contribution of asthma to direct health care expenditure helps to explain the economic impact of the disease.

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 Access Economics 2015; NACA 2018).

In 2020–21, an estimated $851.7 million of expenditure in the Australian health system was attributed to asthma, representing 0.6% of total health expenditure and 19% of expenditure of all respiratory conditions (AIHW 2023c).

Where is the money spent?

In 2020–21:

• primary care represented 74% ($630.5 million) of asthma expenditure, around 2.7 times the primary care portion for all disease groups (28%). The Pharmaceutical Benefits Scheme (PBS) proportion of asthma expenditure was especially large in comparison to the average, 4.7 times the proportion for all disease groups (53% and 11%, respectively)
• hospital services accounted for 21% ($179.9 million) of asthma spending, which was 3.0 times lower than the hospital proportion for all disease groups (63%). The public hospital emergency department proportion of asthma expenditure was especially large in comparison to the average, 1.5 times the proportion for all disease groups (6.2% and 4.1%, respectively)
• referred medical services represented 4.8% ($41.3 million) of asthma expenditure, which was less than the proportion for all disease groups (9.8%) (Figure 5).

Figure 5: Asthma expenditure attributed to each area of the health system, with comparison to all disease groups, 2020–21

In 2020–21, asthma accounted for:

• 2.6% ($450.6 million) of all PBS expenditure – ranking 11th of all diseases/conditions
• 1.4 % ($152.0 million) of all GP expenditure (Figure 6).

Figure 6: Proportion of expenditure attributed to asthma, for each area of the health system, 2020–21

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. 

Between 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
• $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).

Who is the money spent on?

In 2020–21:

• the age distribution of spending on asthma reflects the prevalence distribution, with the majority being spent on older people (55% for people aged 45 and over)
• 1.4 times more asthma expenditure was attributed to females compared with males ($477.5 million and $346.7 million, respectively), with the remaining $27.5 million (3.2%) unattributed to any sex.

In 2018–19, it was estimated that asthma expenditure per case was:

• slightly higher for females compared with males ($290 and $265 per case, respectively)
• 44% lower than respiratory conditions as a group ($285 and $515 per case, respectively) (AIHW 2022).

For more information, see:

• Health system spending per case of disease and for certain risk factors
• Health system spending on disease and injury in Australia, 2020–21.

How many deaths were associated with asthma?

Asthma was recorded as an underlying cause of death for 467 deaths or 1.8 deaths per 100,000 population in Australia in 2022. This represented 0.2% of all deaths and 3.1% of all respiratory deaths in 2022.

Asthma was more likely to be recorded as an associated cause of death and was recorded as such for an additional 2,005 deaths, resulting in a total of 2,472 deaths due to, or associated with, asthma. This represented 1.3% of all deaths and 4.5% of respiratory deaths.

Variation by age and sex

In 2022, asthma mortality rates (as the underlying cause of death):

• increased with increasing age and were highest for people aged 85 and over (39 per 100,000 population) 
• were higher for females compared with males for most age groups. Differences by sex were more pronounced with age (with females aged 85 and over having the highest mortality rate, 46 per 100,000 population, compared with males of the same age, 27 per 100,000 population) 

Asthma mortality rates by age and sex were similar for the underlying cause of death and any cause of death (Figure 7).

Figure 7: Age distribution for asthma mortality, by sex, 2012 to 2022

Trends over time

After adjusting for different population age structures over time, mortality rates for asthma (as the underlying cause of death) between 2012 and 2022:

• changed little over time, ranging between a high of 1.6 per 100,000 population in 2016 and a low of 1.1 per 100,000 population in 2021. For asthma as any cause of death, rates increased from 4.7 to 7.3 per 100,000 population over the same time
• were consistently higher for females compared with males. This pattern is also observed for asthma as any cause of death (Figure 8).

Figure 8: Trends over time for asthma mortality, 2012 to 2022

Variation between population groups

In 2022, after adjusting for age differences, mortality rates for asthma (as the underlying cause of death) changed little by remoteness or level of disadvantage (also known as socioeconomic area). Rates were:

• 1.5 deaths per 100,000 population for people living in Outer regional areas and 1.3 per 100,000 population for those living in Major cities
• 2.0 per 100,000 population for people living in areas of most disadvantage (lowest socioeconomic areas), and 1.1 per 100,000 population for those living in the least disadvantaged areas (highest socioeconomic areas).

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 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 (Stanford Children’s Health 2020).

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.

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

Asthma cycle of care

Asthma cycle of care claims are used as a proxy for asthma GP care since no other data source is available. Claims cover at least 2 asthma-related GP consultations within 12 months.

Analysis of MBS data shows that around 13,000 (0.1%) people made an asthma cycle of care claim in 2021–22, with little difference observed by sex after adjusting for age differences (Figure 9). 

From 2017–18 to 2021–22, the proportion of people making asthma cycle of care claims decreased from 0.3% to 0.1%. (Figure 9).

Figure 9: Proportion of people who claimed the completion of the asthma cycle of care service, by age and sex, 2017–18 to 2021–22

It should be noted that asthma cycle of care items were removed from the Medicare Benefits Scheme (MBS) as of 1 November 2022 and thus future reporting will not be possible (RACGP 2022).

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.

Asthma action plans

An asthma action plan is a written self-management plan, prepared for patients by a health care professional to help them manage their asthma and reduce the severity of acute asthma flare-ups (NACA 2022).

According to the 2020–21 NHS:

• 34% of people who were estimated to have asthma across all ages, had a written asthma action plan
• 69% of children aged under 14 had a plan, compared with 23% of people aged 75 and over (ABS 2022a)
• females were more likely compared with males to have a plan (Figure 10).

Age differences are likely to be due to schools and childcare facilities requiring that children with asthma have a health care provider issued asthma action plan (Asthma Australia 2022).

According to the 2018–19 NATSIHS, 32% of First Nations people had a written asthma action plan, with those living in Non-remote areas more likely to have a plan compared with those living in Remote areas (32% and 27%, respectively) (Figure 10).

For more information, see First Nations people with asthma.

Figure 10: Proportion of people living with asthma with written asthma action plan, by age and sex, and by Indigenous status and remoteness area

What medicines are used to treat asthma?

There are several types of medicines available to treat asthma:

• Relievers are used for the rapid relief of asthma symptoms. 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 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.

Biologics are a relatively new class of medications which are increasingly being prescribed to those with severe asthma. They 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 PBS. Therefore, not all biologics are included in reporting on medications in this section.

Reliever medication use for asthma control

Assessing the overall level of asthma control in the population provides 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 reliever medication is an indicator of poor asthma control, with dispensing frequency used as a proxy for reliever use. In line with advice from the AIHW’s Chronic Respiratory Conditions Expert 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 PBS data showed 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
• the rate of dispensing relievers 3 or more times in 12 months was the same (18%) for males and females aged 0–40
• 26% 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 (Figure 11).

Rates have changed little since 2017–18 but, for all age groups apart from 0–14, a spike was observed in 2020–21 (Figure 11). The corresponding spike for those aged 0–14 is observed earlier, in 2019–20. This same trend is noted for preventer medications (Indicator 8) 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 (Department of Health and Aged Care: Therapeutic Goods Administration 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).

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 age and sex, 2017–18 to 2021–22

Preventer medication use for asthma control

Preventer medicine use is the mainstay of asthma management, to minimise symptoms and exacerbations. National guidelines for the management of asthma recommend preventers are used daily) rather than intermittently (NACA 2022).

In line with advice from the AIHW’s Chronic Respiratory Conditions Expert 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 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. The rate of dispensing preventers 3 or more times in 12 months:

• increased with age from 25% for those aged 15–24, to 41% for those aged 45–50
• was slightly higher for males compared with 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).

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 12). 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.

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

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 age and sex, 2017–18 to 2021–22

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 National Hospital Morbidity Database (NHMD) show that in 2021–22, there were 38,000 hospitalisations with a principal or additional diagnosis (any diagnosis) of asthma, representing 0.3% of all hospitalisations.

The rest of this section discusses hospitalisations with a principal diagnosis of asthma, unless otherwise stated. However, charts and tables also include statistics for any diagnosis of asthma.

In 2021–22:

• there were 25,500 hospitalisations with a principal diagnosis of asthma, representing 0.2% of all hospitalisations in Australia, and 99 hospitalisations per 100,000 population
• asthma accounted for 51,000 bed days, representing 0.2% of all bed days
• 63% of asthma hospitalisations were overnight stays, with an average length of 2.6 days.

Variation by age and sex

In 2021–22, most of the 25,500 hospitalisations for a principal diagnosis of asthma in Australia were for children and young people aged 0–14 (Figure 13). The age profile of hospitalisations for asthma was much younger compared with hospitalisations for all causes in the same year.

In 2021–22, for asthma:

• the hospitalisation rate among children aged 0–14 was markedly higher than the rate among people aged 15 and over (225 and 70 per 100,000 population, respectively)
• boys aged 0–14 were 1.6 times as likely as girls of the same age to be admitted to hospital
• conversely, females aged 15 and over were 2.4 times as likely as males of the same age to be admitted to hospital (Figure 13).

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

Figure 13: Age distribution for asthma hospitalisations, by sex, 2011–12 to 2021–22

Trends over time

From 2011–12 to 2021–22 for children aged 0–14:

• the rate of hospitalisations halved, from 510 to 225 per 100,000 population
• the proportion of overnight hospitalisations decreased from 77% to 62%, while the average length of overnight stays remained relatively stable over the period, and was 1.6 days in 2021–22.

At the same time, for those aged 15 and over:

• the rate of hospitalisations for asthma varied between 68 and 115 per 100,000 population
• the proportion of overnight stays decreased from 77% to 63%, and the average length of overnight stays changed little (3.5 to 3.3 bed days) (Figure 14).

It should be noted that the rate of hospitalisations over the past few years has been affected by the COVID‑19 pandemic. For more information on this, see Chronic respiratory conditions COVID-19 impact.

Figure 14: Trends over time for asthma hospitalisations, 2011–12 to 2021–22

Seasonal variation in asthma hospitalisations

Among children, the peaks for asthma hospitalisations generally occur in late summer (February) and autumn (May) (Figure 15). The peak in February is likely related to respiratory infections associated with returns to school and childcare after the summer break. Lower use of preventer medication during holidays may also contribute.

2020 was an exception to this general trend, and there was a large decrease in hospitalisations in April and May for all age groups (Figure 15). This was likely due to lockdown mandates related to COVID‑19. For more information on the impact of COVID‑19, see Chronic respiratory conditions COVID-19 impact.

Asthma hospitalisations can also be impacted by one-off natural events which occur on a seasonal basis, such as thunderstorms and bushfires. For more information, see What causes asthma.

Figure 15: Monthly variation in hospitalisations due to asthma, by age group, 2017 to 2021

Asthma hospitalisations by Primary Health Care Network

In 2020–21, the 3 PHN areas with the highest 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), after adjusting for age.

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) (Figure 16).

Figure 16: 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 2021–22:

• there were 59,200 emergency department (ED) presentations for asthma, about 240 presentations per 100,000 population
• ED presentation rates were higher for females compared with males overall (260 and 225 per 100,000 population, respectively)
• boys aged 0–14 were 1.6 times as likely as girls of the same age to present to the ED for asthma (Figure 17).

Between 2018–19 and 2021–22, ED presentation rates decreased from 300 to 240 per 100,000 population and were higher for females compared with males.

In 2021–22, asthma ED presentations rates were around twice as high for:

• people living in Remote areas compared with people living in Major cities (420 and 215 per 100,000 population, respectively) 
• people living in areas of most disadvantage (lowest socioeconomic areas) compared with people living in the least disadvantaged areas (highest socioeconomic areas) (320 and 160 per 100,000 population) (Figure 17).

Like asthma hospitalisations, asthma ED presentations can also be impacted by seasonal variation. However, differences observed between 2019 and 2020 are more likely to be due to the 2019–20 bushfire season and the COVID‑19 pandemic.

In 2020, ED presentation rates decreased significantly during the nationwide lockdown from March and increased again from May. Rates for most of 2020 were lower than observed in 2019, likely due to the impact of health protection measures implemented for the pandemic (Figure 17).

Figure 17: Emergency department presentations due to asthma, by age and sex, remoteness area and socioeconomic area, 2021–22, over time (2018–19 to 2021–22) and by month (2019 to 2022)

Comorbidities of asthma

Some people living with asthma also live with other long-term conditions, known as ‘comorbidity’. For people with asthma, living with a comorbid chronic condition can have implications for their health outcomes, quality of life and treatment choices.

According to the NHS, in 2022, an estimated 1.8 million (65%) people who were living with asthma also had one or more other chronic conditions (Figure 18) – the top 3 comorbidities were mental and behavioural conditions (41%), back problems (25%) and arthritis (23%) (Figure 18) (NHS 2023).

Figure 18: Number of selected chronic conditions and types of comorbidity in people with asthma, 2022