COPD

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-1antitrypsin 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).

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.

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

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. 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).


COPD is more common among 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

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: 7.5%25 and 3.1%25, respectively; women: 6.6%25 and 4.0%25, respectively). However, there was no significant difference by remoteness area for men and women.

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).

How does COPD affect quality of life?

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

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. 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

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. 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

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. 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).

Comorbidities

People with COPD often have other chronic diseases and long term chronic conditions. For more information, see COPD, associated comorbidities and risk factors.