Chronic obstructive pulmonary disease (COPD) refers to a group of progressive lung conditions that affect how the lungs work, causing breathing difficulties. The COPD Assessment Test (CAT) is a questionnaire that measures the extent to which COPD affects a person’s life. A CAT score may help guide treatment plans.

COPD is an umbrella term for irreversible lung conditions that cause difficulty breathing and can be life threatening. Many cases of COPD are due to smoking or exposure to other chemicals that affect the lungs. Although there is currently no cure for COPD, treatments can help people manage the symptoms.

Doctors can use different methods to understand how COPD affects a person and ensure that they receive appropriate treatment. One tool that they may use is the CAT, which aims to assess the health status of individuals with COPD to help minimize the burden of the condition and manage the symptoms.

In this article, we discuss what the CAT is, how to calculate the score, and how to interpret the results.

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The CAT is a questionnaire that people with a diagnosis of COPD take to assess their health status. Healthcare professionals use the results to understand the impact that COPD has on the daily life of an individual and monitor how this changes over time. The CAT is a valuable tool for communication between the person with COPD and their healthcare team.

The questionnaire consists of eight simple statements, which people answer using a numerical scale. For each statement, the person with COPD picks the number between 0–5 that reflects their response. A zero indicates no effect on quality of life, whereas a 5 suggests a very significant effect.

A person can complete the test online or on paper. A healthcare professional will review and discuss the results with the individual and may suggest changes to their treatment plan.

The CAT is not a replacement for treatment. It is a tool that people can use to help improve the management of COPD and ensure that they receive the greatest possible benefit from treatment.

Different versions of the questionnaire are available online, including translations in various languages. The CAT Governance Board regulates the use of the CAT and provides the original version. However, people can also use other online versions to calculate their score.

As COPD causes breathing difficulties, the CAT questionnaire focuses on how the lungs are working and how any symptoms affect a person’s general health.

The eight sections cover:

  • frequency of coughing
  • amount of phlegm in the chest
  • tightness in the chest
  • breathlessness when walking up a hill or a flight of stairs
  • how limited the person’s activity is
  • how confident they are leaving their home
  • sleep
  • energy levels

Each section of the test provides statements at either end of the spectrum. People with COPD grade their health in each area from 0–5. For example, they would select zero for “my chest does not feel tight at all” and 5 for “my chest feels very tight.” If someone’s chest feels tight only some of the time, they can choose the most relevant value in between.

Combing these scores will provide a total between zero and 40. A higher score denotes a more severe impact of COPD on a person’s life.

The total score gives healthcare professionals an idea of the severity of COPD symptoms and how the condition affects the individual’s daily life. A doctor may ask the person to take the CAT every 2–3 months so that they can monitor the progression of COPD symptoms and the effectiveness of treatment. This monitoring can help guide future treatment plans.

The scores can provide healthcare professionals with a grading of clinical impact. The clinical impact is the effect that the COPD symptoms have on the individual’s health and daily life. A doctor may use the following ranges to classify severity:

  • 0–9 (low): Guidelines suggest that a person in good health who does not smoke should score 5 or below. A person with a low score may not experience many severe COPD symptoms. They may cough frequently and get breathless during activity, but they can typically function well on most days.
  • 11–20 (medium): A medium score indicates that COPD significantly affects a person’s life. Some days may be good, but the person will often feel breathless and must move slowly. They will cough up phlegm most days and often have a tight chest when they wake up.
  • 21–30 (high): A person with a high score may feel that COPD stops them from functioning well every day. They will likely be tired from coughing, experience chest problems that may disturb their sleep, and be constantly breathless.
  • 31–40 (very high): A very high score indicates a high severity of COPD. People with these scores will likely not have any days when they feel in good health, as their COPD symptoms may prevent them from leaving their home or looking after themselves effectively.

The CAT results can help healthcare professionals understand how COPD affects a person’s life and make recommendations for their treatment plan. The treatment plan will vary depending on the individual’s health, lifestyle, and current medications.

A doctor may look at the following management considerations, depending on a person’s CAT score:

Score 0–10 ( low)

Considerations may include:

  • reviewing current medication
  • recommending that a person stop smoking
  • recommending reducing exposure to any factors that make COPD symptoms worse
  • recommending that a person receive the influenza and COVID-19 vaccines
  • prescribing long-acting muscarinic antagonists (LAMA) or reliever inhalers

Score 11–20 (medium)

Considerations may include:

  • all those in the guidance for people with low scores
  • prescribing inhaled corticosteroids (ICS) and long-acting beta-2 agonists (LABA)
  • referring a person for pulmonary rehabilitation and possible lung transplant evaluation

Score 21–40 (high and very high)

Considerations may include:

  • all those in the guidance for people with medium scores
  • prescribing a triple therapy that combines ICS, LABA, and LAMA
  • prescribing an oxygen supplement

Research investigating the CAT suggests that it is a reliable and consistent method that can help measure how the condition affects a person’s health and daily life.

Global healthcare company GlaxoSmithKline developed the CAT in 2009 as a short and simple method of assessing the impact of COPD. Although other tools — such as the St George’s Respiratory Questionnaire (SGRQ), the Clinical COPD Questionnaire (CCQ), and the Chronic Respiratory Disease Questionnaire (CRQ) — are available, they are more complex and take longer to use.

The CAT can produce results that correlate with these other, more complex questionnaires. The CAT does not replace the use of these other tools, but it can provide a quick and reliable way to generate similar results.

A 2014 systematic review supports the reliability and validity of the CAT. A 2021 study also notes that the CAT score can help capture the overall impact of COPD. Additionally, a 2020 study concludes that the CAT can be a useful and convenient tool in primary care settings to assess the severity of COPD.

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines classify the CAT as a comprehensive assessment of COPD symptoms and a useful tool to measure a person’s health status.

The COPD Assessment Test is a tool that healthcare professionals can use to help assess the health of a person living with COPD. It is a quick and simple numerical scale questionnaire comprising eight statements. The total score out of 40 gives doctors a reliable indication of how severe the impact of COPD is on someone’s life.

The test can be a helpful tool for communication between a person living with COPD and their doctor. An individual can take the test in their own time, and a doctor will review the results to ensure that the person is receiving the greatest possible benefit from their treatment plan.