COPD

What is COPD?

COPD is a serious, progressive condition that limits airflow in the lungs. COPD is characterised by airflow limitation that is not fully reversible with the use of medication. People with COPD may also have a persistent cough with sputum due to excessive mucus production in the airways (known as chronic bronchitis) or evidence of lung tissue destruction, enlargement of the air sacs and further impaired lung function (known as emphysema). The terms COPD, emphysema and chronic bronchitis are often used interchangeably. In 2015, COPD was the third leading specific cause of total disease burden [1]. In 2015–16, COPD cost the Australian health system an estimated $976.9 million, representing 24% of disease expenditure on respiratory conditions and 0.8% of total disease expenditure [2].

COPD may be associated with other chronic conditions such as asthma, respiratory cancers, diabetes and diseases of the heart and blood vessels due to shared risk factors and the effect of COPD on other parts of the body. The main cause of COPD is active smoking or exposure to smoking, however other causes may be involved, such as [3]:

  • smoke from burning fuels of plant or animal origin
  • outdoor air pollution
  • fumes and dust in the workplace
  • childhood respiratory infections
  • chronic asthma.

It can be difficult to distinguish asthma from COPD because the symptoms of both conditions can be similar. Although the current definitions of asthma [4] and COPD [5] overlap, there are some important features that distinguish typical COPD from typical asthma. For example, people with COPD continue to lose lung function despite taking medication, which is not a common feature of asthma. More information on asthma can be found under Asthma.

There is increasing recognition of asthma-COPD overlap (also called asthma-COPD overlap syndrome, or ACOS). Overall, approximately 20% of patients with obstructive airway disease have been diagnosed with both asthma and COPD [6] (for more information on prevalence, see Asthma-COPD overlap 2017). It is important to identify people with asthma-COPD overlap, because they are at higher risk than patients with asthma or COPD alone, and because they should be treated differently from people with asthma or COPD alone [7]. The National Asthma Council Australia & Lung Foundation recently released an information paper on Asthma-COPD overlap, which includes recommendations for the treatment and management of the condition [7].

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 [8]. 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 [8]. The Action Plan can be found here.

Who gets 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. COPD was the second leading cause of total disease burden for men aged 65–74 and 75–84 and the leading cause for women aged 65–74 [1].

The prevalence (the number of cases present in the population at a given time) of COPD is difficult to determine from routine health surveys. Since COPD is formally defined in terms of an abnormality of lung function, accurately estimating the prevalence of the disease requires clinical testing.

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%, an estimated 464,000 people [9]. 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).

A large international study—Burden of Obstructive Lung Disease (BOLD)—tested the lung function of nearly 10,000 people [10]. The BOLD study estimated the prevalence of COPD using spirometry testing plus 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 [11].

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

The bar chart shows the prevalence of COPD among people aged 45 years and over in 2017–18. COPD was more prevalent in women compared with men (6.2%25 and 3.6%25, respectively) among people aged 55–64. However, there was no significant difference in COPD prevalence between men and women in the other age groups.

Notes

  1. COPD here refers to self-reported current and long-term bronchitis and/or emphysema.
  2. Age-standardised to the 2001 Australian Standard Population.
  3. 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: AIHW analysis of ABS 2019 [12] (Data table).

COPD is more common among Aboriginal and Torres Strait Islanders

COPD affects an estimated 8.8% of Indigenous Australians aged 45 and over—approximately 10,300 people [13], based on self-reported data, although this is likely to be an underestimate. The prevalence of COPD (across all age groups) among Indigenous Australians is 2.5 times as high as the prevalence for non-Indigenous Australians after adjusting for differences in age structure [13].

Inequalities

The prevalence of COPD among people (both men and women) 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: 8.0% and 2.6%, respectively; women: 6.9% and 3.9%, respectively).

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

The bar chart shows the prevalence of COPD by remoteness and socioeconomic area among people aged 45 and over in 2017–18. The prevalence of COPD was higher in the lowest socioeconomic area compared with those in the highest area both for men and women (men: 8.0%25 and 2.6%25, respectively; women: 6.9%25 and 3.9%25, respectively). However, there was no significant difference by remoteness area for men and women.

Notes

  1. Remoteness is classified according to the Australian Statistical Geography Standard (ASGS) 2016 Remoteness Areas structure based on area of residence.
  2. Socioeconomic areas are classified according to using  the Index of Relative Socio-Economic Disadvantage (IRSD) based on area of residence.
  3. Age-standardised to the 2001 Australian Standard Population.
  4. 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: AIHW analysis of ABS 2019 [12]  (Data table).

How does COPD affect quality of life?

COPD can interrupt daily activity, sleep patterns and the ability to exercise. People with COPD rate their health worse than people without the condition. In 2017–18, 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

The bar chart shows self-assessed health status among people aged 45 years and over with and without COPD in 2017–18. People with COPD in this age group were less likely to describe themselves as having excellent health (4.9%25 and 17%25, respectively) and very good health (17%25 and 34%25, respectively), and more likely to describe themselves as having poor health (20%25 and 5.4%25, respectively) compared with those without COPD.

Notes

  1. Age-standardised to the 2001 Australian Standard Population.
  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: AIHW analysis of ABS 2019 [12] (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

The bar chart shows psychological distress experienced by people aged 45 and over with and without COPD in 2017–18. People with COPD in this age group were more likely to experience high (19%25 and 8.3%25, respectively) and very high (17%25 and 4.0%25, respectively) levels psychological distress compared with those without COPD.

Notes

  1. 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.
  2. Age-standardised to the 2001 Australian Standard Population.
  3. 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: AIHW analysis of ABS 2019 [12] (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: Pain experienced by people aged 45 and over with and without COPD, 2017–18

The bar chart shows pain experienced by people aged 45 and over with and without COPD in 2017–18. People with COPD in this age group were more likely to experience moderate (36%25 and 23%25, respectively) and severe (22%25 and 7.8%25, respectively) bodily pain compared with those without COPD.

Notes

  1. Bodily pain experienced in the 4 weeks prior to interview.
  2. Age-standardised to the 2001 Australian Standard Population.
  3. 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: AIHW analysis of ABS 2019 [12]  (Data table).

Comorbidities

People with COPD often have other chronic diseases and long term chronic conditions. See COPD, associated comorbidities and risk factors.

References

  1. Australian Institute of Health and Welfare 2019. Australian Burden of Disease Study 2015: Interactive data on disease burden. Australian Burden of Disease Cat. no. BOD 24. Canberra: AIHW.
  2. AIHW 2019. Disease expenditure in Australia. HWE 76. Canberra: AIHW. Viewed 13 June 2019.
  3. Salvi SS & Barnes PJ 2009. Chronic obstructive pulmonary disease in non-smokers. Lancet 374:733–43.
  4. Global Initiative for Asthma (GINA) 2019 Global Strategy for Asthma Management and Prevention.
  5. Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2019. Global Strategy for the Diagnosis, Management and Prevention of COPD.
  6. Gibson PG, MacDonald VM 2015 Asthma-COPD overlap: now we are six. Thorax, 70: 683-691.
  7. National Asthma Council Australia & Lung Foundation Australia 2017. Asthma-COPD overlap. Melbourne, National Asthma Council Australia.
  8. Department of Health 2019. National Strategic Action Plan for Lung Conditions. Canberra: Department of Health.
  9. Australian Bureau of Statistics (ABS) 2018. National Health Survey: First Results, 2017–18. ABS Cat no. 4364.0.55.001. Canberra: ABS.
  10. Buist S, McBurnie MA, Vollmer WM, Gillespie S, Burney P, Mannino DM et al. 2007. International variation in the prevalence of COPD (The BOLD study): a population-based prevalence study. Lancet 370: 741-50.
  11. Toelle BG, Xuan W, Bird TE, Abramson MJ, Atkinson DN, Burton DL et al. 2013. Respiratory symptoms and illness in older Australians: the Burden of Obstructive Lung Disease (BOLD) study. Medical Journal of Australia 198:144–8.
  12. ABS 2019. Microdata: National Health Survey, 2017-18, detailed microdata, DataLab. ABS cat no. 4324.0.55.001. Canberra: ABS. Findings based on AIHW analysis of ABS microdata.
  13. ABS 2013. Australian Aboriginal and Torres Strait Islander Health Survey: First Results, Australia, 2012–13. ABS cat. no. 4727.0.55.001. Canberra: ABS.