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). In 2011, COPD was the fourth leading specific cause of total burden [1]. The terms COPD, emphysema and chronic bronchitis are often used interchangeably. 

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 [2]:

  • 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 COPD from asthma because the symptoms of both conditions can be similar. Although the current definitions of asthma [3] and COPD [4] 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 in the Asthma snapshot.

 

There is increasing recognition of asthma-COPD overlap (also called asthma-COPD overlap syndrome, or ACOS), which affects around 15–20% of people with either diagnosis [5,6]. 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.

Who gets COPD?

COPD predominantly affects middle aged and older people

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 ranked in the top three causes of total burden for those aged 65─74 and 75─84, and was the second highest ranked cause of total burden for men aged 75─84 [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 2014–15 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 5.1%, an estimated 460,400 people [8]. The prevalence did not differ significantly between males and females (5.2% and 4.9% respectively).

A large international study (Burden of Obstructive Lung Disease (BOLD)) tested the lung function of nearly 10,000 people. BOLD estimated the overall prevalence of COPD in 12 countries to be 10% for people aged 40 and over. In Australia, 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 [9].

Figure 1: Prevalence of COPD, ages 45+, by age, 2014–15

The vertical bar chart shows the prevalence of self-reported COPD increased with increasing age, and was highest among those aged 75 and over (9%25), compared to those aged 65–74 (7%25) and 55–64 (5%25). The overall prevalence of COPD among people ages 45 and over was 5%25.

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: AIHW analysis of ABS Microdata, National Health Survey (NHS) 2014–15 (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 [10], 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 [10].

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 2014–15, 22% of those aged 45 years and over with COPD rated their health as poor, compared to 6% of those aged 45 years and over without it. At the same time, 25% of those with COPD rated their health as very good or excellent compared to 50% of those without COPD (Figure 2) [8].

Figure 2: Self-assessed health among people with and without COPD, ages 45+, 2014–15

The vertical bar chart shows that only 2%25 of people aged 45 and over with COPD rated their health as excellent, compared to 16%25 of those without COPD. People aged 45 and over with COPD were more likely to rate their health as fair or poor than those without COPD.

Notes

  1. COPD refers to self-reported emphysema and/or bronchitis.

  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 Microdata, National Health Survey (NHS) 2014–15 (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 (AIHW) 2016. Australian Burden of Disease Study: Impact and causes of illness and death in Australia 2011. Australian Burden of Disease Study series no. 3. BOD 4. Canberra: AIHW.
  2. Salvi SS & Barnes PJ 2009. Chronic obstructive pulmonary disease in non-smokers. Lancet 374:733–43.
  3. Global Initiative for Asthma (GINA) 2018. Global Strategy for Asthma Management and Prevention.
  4. Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2018. Global Strategy for the Diagnosis, Management and Prevention of COPD.
  5. Bateman ED, Reddel HK, van Zyl-Smit RN, Agusti A 2015. The asthma-COPD overlap syndrome: towards a revised taxonomy of chronic airways diseases? Lancet Respir Med; 3:719–28.
  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. Australian Bureau of Statistics (ABS) 2016. National Health Survey: First Results, 2014–15. ABS Cat no. 4364.0.55.001. Canberra: ABS.
  9. 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.
  10. ABS 2013. Australian Aboriginal and Torres Strait Islander Health Survey: First Results, Australia, 2012–13. ABS cat. no. 4727.0.55.001. Canberra: ABS.