Chronic respiratory conditions

What is COPD?

Chronic obstructive pulmonary disease (COPD) is a preventable and treatable lung disease characterised by chronic obstruction of lung airflow that interferes with normal breathing and is not fully reversible. The symptoms of COPD include cough, sputum production, and dyspnoea (difficult or labored breathing). COPD symptoms often don't appear until significant lung damage has occurred, which usually worsens over time (WHO 2020).

It is worth noting that it can be difficult to distinguish COPD from asthma because the symptoms of both conditions can be similar – both have obstruction to the airways, both are chronic inflammatory diseases that involve the small airways (Buist 2003). 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 Asthma .

Additionally, COPD and bronchiectasis share common symptoms of cough with sputum production and susceptibility to recurrent exacerbations (Hurst et al. 2015). Although these two diseases present several common characteristics, they have different clinical outcomes. Therefore, it is very important to differentiate them at early stages of diagnosis, so appropriate therapeutic measures can be adopted (Athanazio 2012). For more information, see Bronchiectasis.

What causes COPD?

COPD results from a complex interaction between genes and the environment. According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD), there are many causes of COPD, which may include:

• Tobacco smoking: both active smoking and passive exposure to smoking. Although cigarette smoking is the most well studied COPD risk factor, it is not the only risk factor and there is consistent evidence from epidemiologic studies that non-smokers may also develop chronic airflow limitation.
• Genetic factors: a small number of people have a form of emphysema caused by a protein disorder called alpha-1 antitrypsin deficiency (AATD). This is where the body finds it difficult to produce one of the proteins (Alpha-1 antitrypsin) which usually protects the lungs. The lack of this protein can make a person more susceptible to lung diseases such as COPD.
• Lung growth and development factors: any factors that affect lung growth during gestation and childhood have the potential for increasing an individual’s risk of developing COPD, such as low birthweight, early childhood lung infections, abnormal lung growth and development (with normal decline in lung function over time) (Lange et al. 2015).
• Environmental factors: working or living in areas where there is dust, gas, chemical agents and fumes, smoke or air pollution.
• Other chronic conditions: such as asthma and chronic bronchitis, which are associated with an increased likelihood of developing COPD (GOLD 2018).

How common is COPD?

The development of COPD occurs over many years and therefore affects mainly middle aged and older people while asthma affects people of all ages. The prevalence of COPD increases with age, mostly occurring in people aged 45 and over.

In the 2017–18 ABS National Health Survey (NHS), the prevalence of COPD (captured here as self-reported emphysema and/or bronchitis) in Australians aged 45 and over was 4.8%, or an estimated 464,000 people (ABS 2018). Overall, the prevalence did not differ significantly between men and women (4.5% and 5.1% respectively), however for those aged 55–64, COPD was more prevalent in women compared with men (6.2% and 3.6%, respectively) (Figure 1).

However, it should be noted that the prevalence of COPD is difficult to determine from routine health surveys. This is because COPD is formally defined in terms of an abnormality of lung function and clinical testing is required to accurately estimate the prevalence of the disease.

In a large international study called the Burden of Obstructive Lung Disease (BOLD) study, the lung function of nearly 10,000 people were tested (Buist et al. 2007). The BOLD study estimated the prevalence of COPD using spirometry testing in addition to questionnaires about respiratory symptoms, health status, and exposure to COPD risk factors. BOLD estimated the overall prevalence of COPD in 12 countries (including Australia, China, Turkey, Iceland, Germany, USA and Canada) to be 10% for people aged 40 and over. In a later study conducted in Australia using a protocol that closely followed that used in the global BOLD study, the prevalence of COPD was estimated to be 7.5% for people aged 40 years and over and 30% for people aged 75 and over (Toelle et al. 2013).

Figure 1: Prevalence of COPD among people aged 45 and over, by sex and age group, 2017–18

Notes

1. COPD here refers to self-reported current and long-term bronchitis and/or emphysema.

2. COPD occurs mostly in people aged 45 and over. While it is occasionally reported in younger age groups, in those aged 45 and over there is more certainty that the condition is COPD and not another respiratory condition. For this reason only people aged 45 and over are included in this graph.

Source: ABS 2019 (Data table).

Aboriginal and Torres Strait Islander people

Based on self-reported data, in 2018–19, 10% of Aboriginal and Torres Strait Islander people aged 45 and over had COPD (an estimated 17,800 people), with a higher rate among females (13%) compared with males (6.7%). The prevalence of COPD among Indigenous Australian was 2.3 times as high as non-Indigenous Australians, after adjusting for difference in age structure (ABS 2020a; ABS 2020b).

Inequalities

The prevalence of COPD among Australians did not differ significantly according to remoteness area.

However, the prevalence of COPD was higher in the lowest socioeconomic area compared with those in the highest area (men: 7.5% and 3.1%, respectively; women: 6.6% and 4.0%, respectively) (Figure 2).

Figure 2: Prevalence of COPD among people aged 45 and over, by sex, remoteness and socioeconomic area, 2017–18

Notes

1. Rates have been age-standardised to the 2001 Australian Standard Population as at 30 June 2001. Age groups: 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75+.
2. COPD occurs mostly in people aged 45 and over. While it is occasionally reported in younger age groups, in those aged 45 and over there is more certainty that the condition is COPD and not another respiratory condition. For this reason only people aged 45 and over are included in this graph.
3. Remoteness is classified according to the Australian Statistical Geography Standard (ASGS) 2016 Remoteness Areas structure based on area of residence.
4. Socioeconomic areas are classified according to using the Index of Relative Socio-Economic Disadvantage (IRSD) based on area of residence.

Source: ABS 2019 (Data table).

Impact of COPD

COPD can interrupt daily activities, sleep patterns and the ability to exercise. People with COPD rate their health worse than people without the condition. In 2017–18, 1 in 5 (20%) of those aged 45 years and over with COPD rated their health as poor, compared with 5.4% of those aged 45 years and over without it. At the same time, 17% of those with COPD rated their health as very good and 4.9% as excellent compared with 34% and 17% (respectively) of those without COPD (Figure 3).

Figure 3: Self-assessed health of people aged 45 and over with and without COPD, 2017–18

Notes

1. Rates have been age-standardised to the 2001 Australian Standard Population as at 30 June 2001. Age groups: 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75+.
2. COPD occurs mostly in people aged 45 and over. While it is occasionally reported in younger age groups, in those aged 45 and over there is more certainty that the condition is COPD and not another respiratory condition. For this reason only people aged 45 and over are included in this graph.

Source: ABS 2019 (Data table).

In 2017─18, people with COPD were more likely to report high (19%) and very high (17%) levels of psychological distress compared to people without COPD (8.3% and 4.0%, respectively) (Figure 4).

Figure 4: Psychological distress experienced by people aged 45 and over with and without COPD, 2017–18

Notes

1. Rates have been age-standardised to the 2001 Australian Standard Population as at 30 June 2001. Age groups: 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75+.
2. COPD occurs mostly in people aged 45 and over. While it is occasionally reported in younger age groups, in those aged 45 and over there is more certainty that the condition is COPD and not another respiratory condition. For this reason only people aged 45 and over are included in this graph.
3. Psychological distress is measured using the Kessler Psychological Distress Scale (K10), which involves 10 questions about negative emotional states experienced in the previous 4 weeks. The scores are grouped into Low: K10 score 10–15, Moderate: 16–21, High: 22–29, Very high: 30–50.

Source: ABS 2019 (Data table).

In 2017–18, people with COPD were more likely to report moderate (36%) and severe (22%) bodily pain compared to people without COPD (23% and 7.8%, respectively) (Figure 5).

Figure 5: Pain experienced by people aged 45 and over with and without COPD, 2017–18

Notes

1. Rates have been age-standardised to the 2001 Australian Standard Population as at 30 June 2001. Age groups: 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75+.
2. COPD occurs mostly in people aged 45 and over. While it is occasionally reported in younger age groups, in those aged 45 and over there is more certainty that the condition is COPD and not another respiratory condition. For this reason only people aged 45 and over are included in this graph.
3. Bodily pain experienced in the 4 weeks prior to interview.

Source: ABS 2019 (Data table).

Deaths

COPD is a major leading cause of death in Australia. In 2018, 7,113 people were recorded as having died from COPD (3,783 men and 3,330 women) making it the fifth leading cause of death after coronary heart disease, dementia and Alzheimer disease, cerebrovascular disease, and lung cancer.

Notes

1. Leading causes of death are based on underlying causes of death and classified using an AIHW-modified version of Becker et al. 2006. International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10) codes are presented in parentheses.
2. Per cent is the per cent of all causes – the proportion of deaths out of total number of deaths.
3. Year refers to year of registration of death. Deaths registered in 2018 are based on preliminary version. preliminary versions are subject to further revision by the Australian Bureau of Statistics (ABS).

Source: AIHW analysis of the AIHW National Mortality Database.
 

It is worth noting that COPD is more likely to be reported as an associated cause of death rather than the underlying cause of death. In 2018, there were 11,385 deaths where COPD was listed as an associated cause in addition to the 7,113 deaths where COPD was listed as the underlying cause.

The statistics presented here relate to deaths where COPD was listed as the underlying cause of death. For information on long-term trends, see General Record of Incidence of Mortality (GRIM) books. For more information on how deaths are registered, coded and updated, see Deaths data.

COPD mortality trends over time

In Australia, the COPD mortality rate among men aged 45 and over decreased dramatically by almost two thirds between 1980 and 2006, from 228 to 84 per 100,000 population, and then fluctuated between 2007 and 2013. After that, it dropped slightly from 2014 (91 per 100,000 population) to 2018 (76 per 100,000 population). Over the same period, the mortality rate for women aged 45 and over fluctuated, with the lowest at 39 per 100,000 population in 1980 and highest at 66 per 100,000 population in 1996.

The main risk factor for the development and progression of COPD is smoking, with smokers being 12 to 13 times more likely to die from COPD than non-smokers (U.S. Department of Health and Human Services 2014). The improvements in COPD mortality rates are expected to follow improvements in smoking rates, with a time-lag between smoking and COPD mortality. This is because chronic conditions, such as COPD, have a long latency period ie. smoking early in life is involved in initiating disease processes prior to disease diagnosed (Lynch & Smith 2005). In Australia, the smoking rate of adults aged 18 and over decreased dramatically from 1980 to 2016 (men: 41% to 16%; women: 30% to 12%) (Scollo & Winstanley 2019).

As shown in Figure 6, smoking rates in Australia have decreased from 1980 onwards among both men and women, with men having consistently higher smoking rates than women (Scollo & Winstanley 2012). For more information on the history of smoking and COPD, see Mortality from asthma and COPD in Australia, which presents detailed analysis of COPD mortality for the period 1965 to 2010.

Figure 6: Smoking rate (per cent) of people aged 18 and over and age‑standardised death rate (per 100,000 population) due to COPD, people aged 45 and over, by sex, 1980–2016

Notes

1. COPD death rates are shown as a 3-year moving average. These rates have been age-standardised to the 2001 Australian Standard Population as at 30 June 2001. Age groups: 45–49, 50–54, 55–59, 60–64, 65–69, 70–74, 75–79, 80–84, 85+.
2. From 1979 to 1996, COPD classified according to ICD-9 codes 490, 491, 492, 496; from 1997 to 2017, COPD classified according to ICD-10 codes J40–J44. COPD occurs mostly in people aged 45 years and over. While it is occasionally reported in younger age groups, in those aged 45 years and over there is more certainty that the condition is COPD and not another respiratory condition. For this reason only people aged 45 years and over are included in this graph.
3. Smoking refers to people those reporting that they smoke 'daily' or 'at least weekly', and smoking any combination of cigarettes, pipes or cigars.
4. Smoking data were calculated by the Cancer Council of Victoria. Smoking rates for 1980–1992 were sourced from surveys conducted by the Anti-Cancer Council of Victoria; smoking rates for 1995–2016 were sourced from the National Drug Strategy Household Survey. Blank cells mean that data was not available.
5. Year refers to year of registration of death. Deaths registered in 2015 and earlier are based on the final version of cause of death data; deaths registered in 2016 are based on revised version; and deaths registered in 2017 and 2018 are based on preliminary version. Revised and preliminary versions are subject to further revision by the Australian Bureau of Statistics (ABS).

Sources: AIHW analysis of AIHW National Mortality Database, Scollo & Winstanley 2019 (Data table).

Higher death rate from COPD in certain population groups

COPD mortality rates are higher for people living in remote areas and for people living in lower socioeconomic areas (AIHW: Poulos et al. 2014). In 2018, the COPD mortality rate for those aged 45 and over living in Remote and very remote areas (103 deaths per 100,000 population) was 1.9 times as high as the rate for those living in Major cities (54 deaths per 100,000 population). Meanwhile, the COPD mortality rate for this same age group in the lowest socioeconomic areas (102 deaths per 100,000 population) was 2.8 times as high as the rate in the highest areas (36 deaths per 100,000 population).

COPD mortality rates are also higher for Indigenous Australians. In the 5-year period from 2014 to 2018, 835 Aboriginal and Torres Strait Islander people aged 45 and over died from COPD, with a mortality rate of 114 per 100,000 population, based on the five jurisdictions with adequate Indigenous identification (NSW, Qld, WA, SA and NT). After adjusting for differences in age structure, for people aged 45 and over, the mortality rate of COPD among Indigenous Australians (189 per 100,000 population) was 2.7 times as high as the non-Indigenous Australians rate (70 per 100,000 population).

The differences between these population subgroups may be due to differences in smoking rates, access to health services, or other factors. Smoking rates are higher among people living in more remote areas, among people living in areas of lower socioeconomic area, and among Indigenous Australians (AIHW 2018).

For more information about COPD mortality rates among Indigenous Australians, see Coronary heart disease and chronic obstructive pulmonary disease in Indigenous Australians.

Burden of disease

Burden of disease measures the gap between the ideal of living to old age in good health, and the current situation where healthy life is shortened or lost by illness, injury, disability and death (AIHW 2019a). It combines health loss from living with illness and injury (non-fatal burden, or years lived with disability [YLD]) and dying prematurely (fatal burden, or years of life lost [YLL]) to estimate total health loss (total burden, or disability-adjusted life years [DALY]). One DALY is one year of 'healthy life' lost due to illness and/or death.

In Australia, COPD accounted for over half (51%) of the total burden of disease due to respiratory conditions and 3.9% of the total disease burden in 2015 (AIHW 2019a). Between 2003 and 2015, there was a 6.0% decrease in the total disease burden due to COPD. 

Overall, COPD was the third leading specific cause of total disease burden. COPD is the leading cause of total burden in women aged 65–74 (22.6 DALYs per 1,000 population), and the second leading cause of total burden in men aged 65–74 (33.2 DALYs per 1,000 population) and 75–84 (54.3 DALYs per 1,000 population). The total disease burden due to COPD was split fairly evenly between non-fatal burden (51%) and fatal burden (49%) in 2015 (AIHW 2019a).

For both men and women, the rate of total burden (DALY) increased with age, peaking at ages 85–94 then decreasing. The rate of fatal burden (YLL) followed a similar pattern. However, the rate of non-fatal burden (YLD) for men was highest among those aged 75–84 (Figure 7).

Figure 7: Burden of disease due to COPD, people aged 45 and over, age-specific rate, by sex and age group, 2015

Variation across population groups

The disease burden due to COPD varies in different population groups. The COPD DALY rate in Remote and very remote areas was 1.3 times as high as in Major cities. Meanwhile, the COPD DALY rate in the lowest socioeconomic area was 1.8 times as high as in the highest group.

Figure 8: Burden of disease due to COPD, age-standardised rate, by remoteness and socioeconomic area, 2015

Disease expenditure

In 2015–16, COPD cost the Australian health system an estimated $977 million, representing 24% of disease expenditure on respiratory conditions and 0.8% of total disease expenditure (AIHW 2019b). This expenditure consisted of:

• $536 million for hospitals (55% of total expenditure on COPD)
• $189 million for non-hospital medical services (19%)
• $252 million for pharmaceuticals (26%)

Figure 9: Health expenditure on COPD, by area of expenditure and sex, 2015–16

Treatment and management of COPD

The Department of Health’s National Strategic Action Plan for Lung Conditions (the Action Plan) provides a detailed, person-centred roadmap for treating and managing COPD, among several other lung conditions (Department of Health 2019). The Action Plan outlines a comprehensive, collaborative and evidence-based approach to reducing the individual and societal burden of lung conditions and improving lung health (Department of Health 2019). The Action Plan can be found on the Lung Foundation Australia website.

Also, the COPD-X Plan: Australian and New Zealand Guidelines for the management of Chronic Obstructive Pulmonary Disease (the COPD-X Guidelines) summarises current evidence around optimal management of people with COPD, and provides a decision support aid for general practitioners, other primary health care clinicians, hospital-based clinicians and specialists working in respiratory health. The evidence published in the COPD-X Guideline is systematically searched for, identified and reviewed on a regular basis (Lung Foundation Australia 2019).

COPD-X stands for:

• Case finding and confirm diagnosis
• Optimise function
• Prevent deterioration
• Develop a plan of care
• Manage eXacerbations (Lung Foundation Australia 2019).

The latest COPD-X Guidelines can be found on the Lung Foundation Australia website.

What role do GPs play in treating and managing COPD?

General practitioners (GPs) are often the first point of contact for people who develop COPD. According to the Bettering the Evaluation and Care of Health (BEACH) survey, in the ten-year period from 2006–07 to 2015–16, the estimated rate of COPD management in general practice was around 0.9 per 100 encounters (Figure 10) (Britt et al. 2016).

Figure 10: General practice encounters for COPD, all ages, 2006–07 to 2015–16

Notes

1. COPD classified according to International Classification of Primary Care, 2nd edition (ICPC-2) codes R79001, R79003 and R95.
2. The Bettering the Evaluation and Care of Health (BEACH) year is from April to March.
3. An encounter relates to a consultation between a patient and a GP.
4. Statistics on general practice activities based on BEACH data are derived from a random sample survey of GPs and their encounters with patients, and should be interpreted with caution.

Source: Britt et al. 2016 (Data table).

What interventions are used to treat and manage COPD?

Currently, the only intervention that has been shown to slow the long term deterioration in lung function associated with COPD is assisting smokers to quit (Mosenifar 2019). Other interventions for COPD that can help maintain quality of life and reduce symptoms are: immunisations, pulmonary rehabilitation, medications, and, for people with very severe disease, long-term oxygen therapy.

Some information is available on use of medications by patients with COPD, however, there is currently a lack of nationally comparable information about access to and utilisation of pulmonary rehabilitation and oxygen therapy. Options for improving data about these interventions are discussed in the report Monitoring pulmonary rehabilitation and long-term oxygen therapy for people with chronic obstructive pulmonary disease (COPD) in Australia – a discussion paper.

Smoking cessation

The most beneficial step in any treatment plan for COPD patients is to stop smoking. Stopping smoking is the only intervention that has been shown to improve the natural progression of COPD. For example, it helps to improve a patient’s cough, ease breathlessness and slow down further lung damage (Lung Foundation Australia 2020).

Immunisation

Vaccination reduces the risks associated with influenza and pneumococcal infection, which are leading causes of exacerbations and healthcare visits. Therefore, influenza immunisation and pneumococcal immunisation is recommended for all patients with COPD (Lung Foundation Australia 2019).

Pulmonary rehabilitation

Pulmonary rehabilitation is one of the most effective interventions for COPD, and is recommended for all patients with COPD who are short of breath on exertion, including in the period following an acute exacerbation (Spruit et al. 2013; Alison et al. 2017). According to Spruit, pulmonary rehabilitation is a comprehensive intervention, mainly involving exercise training, education, and behaviour change. It is designed based on a thorough patient assessment followed by patient-tailored therapies (Spruit et al. 2013). Strong evidence supports pulmonary rehabilitation is effective for COPD patients to improve their physical and emotional condition, long-term adherence to health behaviours, quality of life and reduce hospitalisations, thus helping them improve their independence and functioning in the community (Gordon et al. 2019; McCarthy et al. 2015; Puhan et al. 2016).

Pulmonary rehabilitation is commonly delivered by an interdisciplinary team of therapists, and may comprise various associated supportive strategies (Lung Foundation Australia 2008). It mainly includes the following components:

• Exercise training – the cornerstone foundation of pulmonary rehabilitation. This aims to build patient confidence, maximise skeletal muscle function, optimise cardiovascular fitness and promote self-sustaining healthy physical activity behaviours.
• Education – involves the provision of tailored advice to improve people’s understanding of their lung disease, awareness of self-management strategies, how to exercise safely, how to use medicines, how treatment works, and when to ask for help. Education may be provided in various formats such as group discussions or resources. Identifying individual support needs (e.g. assistance to quit smoking) is an essential goal of education.
• Nutrition counselling – the provision of individually tailored dietary support to optimise nutritional intake and control weight loss or gain. In people with COPD, both excess weight and low weight are associated with increased morbidity. Obesity increases the work of breathing, while poor nutritional status and insufficient energy intake may lead to impaired muscle function, which can accelerate deconditioning and worsen symptoms such as breathlessness.
• Psychosocial support – People with COPD are vulnerable to developing symptoms of anxiety and depression, which can worsen quality of life and disability. Support is often provided by peer participants, support groups, social workers or external organisations. This may involve emotional support, social support, or the development of coping strategies to help people better manage COPD. Mental health specialists may provide additional expert support, if required, for clinically significant symptoms of anxiety or depression (Lung Foundation Australia 2017; Yang et al. 2018).

Pulmonary rehabilitation may be provided in hospital outpatient departments, in community facilities or at home. Hospital-based programs are often considered ‘usual care’, however community-based programs of equivalent frequency and intensity can be offered to people with COPD as a suitable alternative (Lung Foundation Australia 2017). Home-based pulmonary rehabilitation programs should include regular contact with an exercise specialist to facilitate appropriate participation and progression.

Medications

Medications are used in COPD treatment to prevent and control symptoms, reduce the frequency and severity of exacerbations and improve exercise tolerance. Some drugs used to treat COPD are also used to treat other respiratory conditions such as asthma. For more information, see Respiratory medication use in Australia 2003–2013: treatment of asthma and COPD.

Several medications are available for treatment of COPD in Australia, including long-acting bronchodilators used both separately and in combination with inhaled corticosteroids or other bronchodilators. Bronchodilators are drugs that can relax and dilate the bronchial passage ways and therefore improve the passages of air into the lungs. It is worth mentioning that the majority of the medications used in COPD treatment are delivered via inhalers, so good inhaler technique and adherence to treatment are important for optimal treatment outcome (George & Bender 2019).

Oxygen therapy

Long term oxygen therapy (LTOT) – the provision of supplemental oxygen therapy for 15 hours per day or more – can be prescribed for people with persistently low levels of oxygen in the blood, including from chronic lung disease, most commonly advanced COPD. LTOT reduces mortality in COPD and may also have a beneficial impact on aspects of quality of life (Yang et al. 2018). Although effective, it is a potentially expensive and cumbersome therapy that should only be prescribed for those in whom there is evidence of benefit (Yang et al. 2018). In Australia, LTOT is mostly delivered in the home using an oxygen concentrator, a device that removes nitrogen from room air, thereby increasing the concentration of oxygen. Sometimes oxygen cylinders are provided for short-term or portable use.

Non-invasive ventilation

Non-invasive ventilation (NIV) refers to the administration of ventilatory support using a face mask, nasal mask, or a helmet, rather than an invasive artificial airway (such as a tube). Air, usually with added oxygen, is given to patient through the mask under positive pressure, where the amount is alterated depending on whether the patient is breathing in or out. NIV has now become an integral tool in the management of acute and chronic respiratory failure, in both the home setting and in the critical care unit.

The current evidence shows that NIV is effective in preventing respiratory failure after extubation (removal of a tube previously inserted into a patient's body) (Ferrer et al. 2009), and treating patients with an acute exacerbation of COPD and other disorders characterised by hypoventilation (Ram et al. 2004; Osadnik 2017).

What role do hospitals play in treating COPD?

Patients may require admission to hospital for severe acute exacberations of COPD. Acute exacerbations of COPD (flare-ups) are frequently due to respiratory tract infections. They have also been associated with increases in exposure to air pollution and changes in ambient temperature. Episodes that are life threatening sometimes require temporary assistance with breathing.

Data from the AIHW National Hospital Morbidity Database (NHMD) show that in 2020-21 there were 53,600 hospitalisations of people 45 and over where COPD was the principal diagnosis. The rate of hospitalisation for COPD among those aged 45 and over was 510 per 100,000 population. Both the rate of hospitalisations and the average length of stay in hospital tended to increase with increasing age (Figure 11).

Figure 11. Rate of hospitalisation for COPD, by sex and age, 2020–21

The hospitalisation rate for Australians aged 45 years and over has declined annually from its peak in 2016–17, from 850 to 530 per 100,000 population for men in 2020–21, and from 760 to 485 per100,000 population for women in 2020–21.  The average length of stay has also declined steadily for both males and females from 6.8 days in 2010-11 to 5.3 days in 2020–21 (Figure 12).

Figure 12: Hospitalisation rate due to COPD, people aged 45 and over, by sex, 2010–11 to 2020–21

COPD exacerbations are strongly driven by seasonality

Admissions to hospital for COPD are highest in winter and early spring and is consistent with the trend for acute respiratory infections, such as rhinovirus (common cold), influenza, pneumonia and acute bronchitis (Figure 13). 

2020 was an exception to this general trend, and hospitalisations were lower overall across the entire year. This is likely due to lockdown mandates related to COVID-19 across the nation.

Figure 13: Hospitalisations due to acute respiratory infection (ARI) and COPD, by month, 2016–2020

Comorbidities of COPD

People with chronic obstructive pulmonary disease (COPD) often 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). Comorbidities often share common risk factors, and are increasingly seen as acting together to determine the health outcome.

Australians diagnosed with one or more chronic conditions often have complex health needs, die prematurely and have poorer overall quality of life (AIHW 2018). In terms of comorbidities, in 2017─18 one in five Australians (20%) had two or more chronic conditions (ABS 2018). As people age, they are more likely to have more than one chronic condition. Because COPD is more likely to occur in older people, people with COPD also commonly experience a range of other chronic conditions (Chatlia et al. 2008; Divo et al. 2012). These comorbidities contribute to ill health and risk of death in all stages of COPD, and the incidence of hospitalisation for non-respiratory causes is increased in patients with COPD (Franssen & Rochester 2014). As well, when people are admitted for non-respiratory causes, they have a longer length of hospital stay and are more likely to die if they also have COPD (Holguin et al. 2005).

The chronic conditions that have been selected for this COPD comorbidity analysis are: arthritis, asthma, back problems, cancer, diabetes, heart, stroke and vascular disease, kidney disease, mental and behavioural conditions and osteoporosis. They have been selected because they are common in the general community and cause significant burden. Other chronic conditions that are found commonly in people with COPD, and that can impact COPD, include bronchiectasis and obstructive sleep apnoea (LunMonitoring pulmonary rehabilitationg Foundation Australia & the Thoracic Society of Australia and New Zealand 2019). COPD is also associated with an increased risk of lung cancer and gastro-oesophageal reflux disease (GORD) (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019).

In February 2019, the Department of Health released the National Strategic Action Plan for Lung Conditions (the Action Plan), which includes COPD in its scope. The Action Plan ‘provides a detailed, person-centred roadmap for addressing one of the most urgent chronic conditions facing Australians’ (Department of Health 2019). The Action Plan ‘outlines a comprehensive, collaborative and evidence-based approach to reducing the individual and societal burden of lung conditions and improving lung health’ (Department of Health 2019). The Action Plan acknowledges as with most chronic conditions, lung disease may co-exist with other common chronic conditions. The Action Plan addresses these comorbidities when clinically relevant to a patient living with lung condition(s) (Department of Health 2019). For more information, see National Strategic Action Plan for Lung Conditions.

Comorbidities can complicate management options and multiply the effects of chronic conditions (Van der Molen 2010). Physicians may need to prescribe medications for one condition that may exacerbate another existing comorbid condition. For example, some bronchodilator medications prescribed for COPD may worsen glaucoma (increased pressure in the eyes), or can cause urinary problems in men with an enlarged prostate. Use of steroid tablets for COPD exacerbations (or flare-ups) may contribute to weakening of the bones (osteoporosis) (AIHW 2019c).

COPD has a high rate of comorbidity with cardiovascular disease (CVD) (Bhatt et al. 2014). Beta‑blocker medications are recommended for management of acute coronary syndromes, cardiac failure and sometimes for irregular heartbeat and hypertension. However, these medications can cause severe flare-ups in people with asthma and so have frequently been withheld from people with COPD (AIHW 2019c). Despite this, recent evidence suggests that beta-blockers may be safe and helpful for managing COPD (Bhatt et al. 2016), though the COPD-X Plan states that despite a paucity of evidence to suggest harm, beta-blockers are still under-utilised in COPD for guideline-based indications such as systolic heart failure (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019).

Establishing a better understanding of the common comorbidities of COPD may help with the diagnosis of comorbid conditions. For example, coronary artery disease is common in patients with COPD and is underdiagnosed (Reed et al. 2012). Optimal management of any individual patient with COPD should include identification and management of comorbidities and anticipation of increased risks associated with those comorbidities in the presence of COPD (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019).

Prevention and diagnosis can be improved by a better understanding of risk factors for the development of COPD. Tobacco smoking, air pollution, poor nutrition and serious childhood lung infections are all known risk factors for developing COPD (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand, 2019). More information on risk factors can be found in the section Risk factors associated with COPD.

Treatment strategies that target modifiable behaviours can be used to manage various chronic diseases, for example, diet, exercise, weight control, and smoking cessation or reduction (Bauer et al. 2014). Smoking cessation is the most important intervention to prevent the worsening of COPD (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019).

Number of comorbid chronic conditions in people with COPD

Based on self-reported data from the 2017–18 National Health Survey (NHS), an estimated 599,000 Australians (2.5% of the population) have COPD (ABS 2018a). While COPD is occasionally reported in younger age groups, in those aged 45 and over there is more certainty that the condition is COPD and not another respiratory condition. The 2017–18 NHS estimates that 464,000 (4.8%) Australians aged 45 and over had COPD (ABS 2019). Eighty six per cent of people who had COPD also had one or more of the following selected chronic conditions (ABS 2018a):

• arthritis
• asthma
• back problems
• cancer
• diabetes
• heart, stroke and vascular disease
• kidney disease
• mental and behavioural conditions
• osteoporosis.

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 (AIHW 2013; AIHW 2015).

Additional chronic conditions that are commonly found in people with COPD, and that can impact on COPD, include bronchiectasis (a condition in which the airway walls are damaged and the person has excessive mucus production and frequent chest infections) and obstructive sleep apnoea (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019).

Of those aged 45 and over who had COPD, 90% had at least one other chronic condition while just 10% had COPD and no other selected chronic conditions (Figure 14). Nearly 1 in 5 (18%) had one other selected chronic condition and over 2 in 3 (72%) had two or more other selected chronic conditions.

Figure 14: Comorbidity of selected chronic conditions in people aged 45 and over with COPD, 2017–18

Note: The 9 other selected chronic conditions include arthritis, asthma, back problems, cancer, diabetes, heart, stroke and vascular disease, kidney disease, mental and behavioural conditions and osteoporosis.

Source: ABS 2019 (Data table).

Types of comorbid chronic conditions in people with COPD

Among people aged 45 and over with COPD:

• 55% had arthritis (compared with 33% for people without COPD)
• 43% had asthma (compared with 11% for people without COPD)
• 41% had mental and behavioural conditions (compared with 21% of people without COPD)
• 40% had back problems (compared with 25% for people without COPD)
• 26% had heart, stroke and vascular disease (compared with 10% of people without COPD) (Figure 15)

Figure 15: Prevalence of other chronic conditions in people aged 45 and over with and without COPD, 2017–18

Notes

1. COPD here refers to self-reported current and long-term bronchitis and/or emphysema.
2. Proportions may not add to 100% as a person may have more than one additional diagnosis.

Source: ABS 2019 (Data table).

Risk factors associated with COPD

COPD shares a number of risk factors with other chronic conditions, such as:

• Non-modifiable risk factors

• age (COPD is more common as people age)
• genetic predisposition (AIHW 2019d)

• Modifiable risk factors

• smoking or exposure to environmental tobacco smoke (including in childhood)
• exposure to fumes and smoke from carbon-based cooking and heating fuels, such as charcoal and gas
• occupational hazards (for example, exposure to pollutants and chemicals)
• poor nutrition
• pneumonia or childhood respiratory infection (AIHW 2019d).

In people with COPD, risk factors for poor health outcomes such as worsening symptoms, exacerbations (flare-ups) and increased risk of death include (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019):

• smoking and exposure to environmental tobacco smoke
• influenza and pneumococcal infection
• malnutrition/ obesity
• insufficient physical activity
• presence of comorbidities

For COPD, as for many other chronic conditions, there are two types of risk factors: those that increase the chance of developing COPD in the first place, and those that increase the chance that a person who already has COPD will develop additional health problems. Risk factors also vary according to the person's age.

Finding a factor that is associated with an increased risk of developing COPD, or an increased risk of poor health outcomes in COPD, does not necessarily mean that the risk factor caused these problems, or that they can be prevented. However, there is overwhelming evidence that smoking and exposure to biomass fuels are major causes of COPD (AIHW 2019d).

Common risk factors

Based on the 2017–18 National Health Survey (NHS), people with self‑reported COPD aged 45 and over were more likely to be current daily smokers and insufficiently physically active, compared with those without COPD aged 45 and over (see Figure 16). Risk factor definitions are included in Box 1 (under data notes). These risk factors are also common among other chronic conditions (ABS 2018a).

Figure 16: Prevalence of selected risk factors in people aged 45 and over with and without COPD, 2017–18

Note: Obese is based on body mass index (BMI) for persons whose height and weight was measured and imputed. In 2017–18, 33.8% of respondents aged 18 years and over did not have a measured BMI. For these respondents, imputation was used to obtain BMI. For more information, see Appendix 2: Physical measurements in the 2017–18 National Health Survey (ABS 2018).

Source: ABS 2019a (Data table).

Selected risk factors

Smoker status

People with COPD aged 45 and over were more likely to be current daily or ex-smokers, with:

• 25% being a current daily smoker (compared with 12% without COPD aged 45 and over)
• 47% being an ex-smoker (compared with 38% without COPD aged 45 and over) (Figure 17).

It is worth noting that one quarter (26%) of people aged 45 and over with COPD had never smoked cigarettes.

Tobacco smoking is one of the leading behavioural risk factors for death from all causes and contributes significantly to deaths from a range of chronic conditions (including CVD, COPD, and lung cancer) (AIHW 2019d). Tobacco smoking is the predominant cause of COPD and is associated with a majority of COPD cases (Yawn & Kaplan 2008). Lifelong smokers have a 50% probability of developing COPD during their lifetime (Laniado-Laborin 2009).

Once COPD has developed, continued smoking increases the risk of exacerbations (flare-ups) and the risk of death, not only from COPD but also from other causes, such as cancer and cardiovascular disease (AIHW 2019d). While the damage from past smoking is not fully reversible, the rate of progression of COPD can be reduced through smoking cessation (Laniado-Laborin 2009). Quitting smoking also reduces the risk of exacerbations and mortality in patients with COPD (Anthonisen et al. 2005; Au et al. 2009).

General Practitioners play an important role in encouraging and supporting people to quit smoking, especially when they have health problems caused or exacerbated by smoking, which are more common with age (Royal Australian College of General Practice 2014). In Australia, smoking rates have been falling amongst males since the 1950s (1970s in women) (Greenhalgh et al. 2019), and recent studies have shown that smoke free laws, tobacco price increases and mass media campaigns have all contributed to a continuing decline in smoking rates, including among young people (Wakefield et al. 2014)

Figure 17: Smoker status of people aged 45 and over with and without COPD, 2017–18

Source: ABS 2019a (Data table).

Physical activity

People with self-reported COPD aged 45 and over were more likely than people without COPD aged 45 and over to be insufficiently physically active (76% compared with 60% for people without COPD) (Figure 18).

One of the main features of COPD is shortness of breath on exertion. As the condition progresses, shortness of breath can worsen and even minor physical activities, such as dressing or showering can become very difficult. People with COPD therefore are often unable to exercise as much as those without COPD, or they may limit their physical activity to avoid becoming short of breath. However, low physical activity in turn leads to lack of cardiovascular fitness, increased risk of cardiovascular disease, and obesity, each of which may further worsen shortness of breath (AIHW 2019d).

Exercise-based pulmonary rehabilitation is an important part of management of COPD, as it improves quality of life and exercise capacity and reduces hospitalisations (Alison et al. 2017). It is a system of care that includes education, exercise training and psychosocial support delivered by an interdisciplinary team of therapists (Alison et al. 2017). Pulmonary rehabilitation reduces symptoms, disability and handicap, reduces hospitalisation and improves physical and emotional function. It can help people achieve and maintain an optimal level of independence and functioning in the community (Alison et al. 2017). For more information regarding pulmonary rehabilitation, refer to Monitoring pulmonary rehabilitation and long-term oxygen therapy for people with chronic obstructive pulmonary disease (COPD).

Figure 18: Physical activity in people aged 45 and over with and without COPD, 2017–18

Source: ABS 2019a (Data table).

Body mass

People with self-reported COPD aged 45 and over were not significantly more likely to be obese compared with people without COPD (43% with COPD compared with 38% without COPD) (Figure 19).

Several studies have shown strong associations between overweight and obesity, as measured by body mass index (BMI), and increased prevalence of COPD (Fuller-Thoson et al. 2018). This is not surprising, as the prevalence of both COPD and obesity increase with increasing age. There is little evidence that high BMI increases the risk of developing COPD. However, obesity is a risk factor for dyspnoea (or shortness of breath), which may contribute to symptoms of COPD and may also reduce lung function (AIHW 2019d).

For patients who already have COPD, many studies have shown that mild obesity appears to be protective from risk of death, unlike many other chronic diseases in which increased body weight is associated with worse outcomes (Hanson et al. 2014; Spelta et al. 2018). Being underweight or average weight is associated with increased risk of dying for people with COPD (Hanson et al. 2014). The relationship between low BMI and increased mortality is particularly seen in patients with more severe COPD, of whom around 14% experience substantial weight loss and reduced fat-free mass (van der Molen 2010). This may be due to systemic inflammation associated with COPD, leading to muscle wasting (van der Molen 2010). Reduced micronutrient intake may also contribute to increased risk (Hanson et al. 2014).

Figure 19: Body mass index (BMI) distribution in people aged 45 and over with and without COPD, 2017–18

Note: Based on body mass index (BMI) for persons whose height and weight was measured and imputed. In 2017–18, 33.8% of respondents aged 18 years and over did not have a measured BMI. For these respondents, imputation was used to obtain BMI. For more information, see Appendix 2: Physical measurements in the 2017–18 National Health Survey (ABS 2018).

Source: ABS 2019a (Data table).

Age differences in risk factors in people with COPD

People with COPD aged 45–64 were more likely to be a current daily smoker (38%) compared with those aged 65 and over (14%) and were less likely to be insufficiently physically active (68%) compared with people with COPD ages 65 years and over (82%). The difference in obesity between the two age groups was not statistically significant (Figure 20).

Figure 20: Prevalence of selected risk factors in people aged 45 and over with COPD, by age group, 2017–18

Note: Overweight and obese are based on body mass index (BMI) for persons whose height and weight was measured and imputed. In 2017–18, 33.8% of respondents aged 18 years and over did not have a measured BMI. For these respondents, imputation was used to obtain BMI. For more information, see Appendix 2: Physical measurements in the 2017–18 National Health Survey (ABS 2018).

Source: ABS 2019a (Data table).