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COPD severity is determined according to a combination of factors, in accordance with lung health guidelines. These guidelines can differ from country to country, which can result in some mixed messages or possible confusion. The information below relates to the Australian and New Zealand COPD-X guidelines.

COPD Severity

  Mild Moderate Severe
Lung function (FEV1)* 60-80% predicted 40-59% predicted <40% predicted
Typical symptoms Few symptoms
Breathless on moderate exertion
Little or no impact on daily activities
Breathless walking on level ground
Increased limitation with daily activities
Breathless with minimal exertion
Symptoms significantly restrict daily activities
History of flare-ups Frequency and severity increase →
  Recurrent chest infections
Flare-ups requiring corticosteroids / antibiotics
Frequent flare-ups and hospital admissions
Co-existing medical conditions ← Present throughout →

* FEV1 is the maximum amount of air a person is able to expire in the first second following their biggest breath in. Average values according to age and gender have been calculated for healthy individuals and the FEV1 results from the person’s lung function test (spirometry) is compared against these predicted values to determine the degree of airflow limitation.

In most cases, deterioration happens over several years and it is difficult to predict when the end of life will be for someone with COPD. Learn more about the physical signs of the last days and what to expect.

Disease progression

Many effective treatments are available to help manage specific aspects of COPD. Despite this, COPD is a disease associated with progressive decline over time. It is not easy to predict the rate at which COPD will progress for individuals as this is influenced by many factors.

Examples of factors that may improve (slow) or worsen (accelerate) the rate of decline are shown below.