COPD assessment test (CAT)

Assessment and monitoring of disease

Assessment of a COPD patient should be carried out to guide management and should include the level of airflow limitation, impact on the patient's health status and the risk of future events (such as exacerbation, hospital admissions or death) (1).

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) recommends that COPD assessment should consider the following aspects of the disease separately:

• presence and severity of the spirometric abnormalities
  • the severity of airflow limitation is classified according to post-bronchodilator FEV1
  • in patients with FEV1/FVC <0.70

• current nature and magnitude of the patient's symptoms
  • COPD was considered to be a condition largely characterised by dyspnoea, hence Modified British Medical Research Council (mMRC) questionnaire was used to assess the symptoms
  • however, it is recommended that a more comprehensive assessment of symptoms should be used since symptoms other than dyspnoea also impact a patient's life
    • questionnaires such as Chronic Respiratory Questionnaire (CRQ) and St. George's Respiratory Questionnaire (SGRQ) have been shown to be too complex to use in routine clinical practice
    • shorter questionnaires have been developed which can be used in daily practice e.g. - COPD Assessment test (CAT), the COPD Control Questionnaire (The CCQ)
      

GOLD ABE Assessment Tool

The "ABE" assessment tool has been developed by GOLD which incorporates a patient's symptomatic assessment with spirometric classification and/or risk of exacerbation.

• in the revised assessment scheme, patients should
  • undergo spirometry to determine the severity of airflow limitation (e.g. - spirometric grade)
  • undergo assessment of dyspnoea using mMRC or symptoms using CAT
  • have their history of moderate or severe exacerbation (including prior hospitalisation) recorded
• this assessment tool recognises the limitation of FEV1 in making treatment decisions in individual patients and highlights the importance of patient symptoms and exacerbation risks in determining COPD treatment
• furthermore, this will help more precise treatment recommendations based on parameters that are driving the patient's symptoms at any given time (1)

GOLD criteria (1)

Classification of severity of airflow limitation in COPD: In pulmonary function testing, a post-bronchodilator FEV1/FVC ratio of <0.70 is commonly considered diagnostic for COPD.

The GOLD system categorises airflow limitation into stages. In patients with FEV1/FVC <0.70:

• GOLD 1 - mild: FEV1 ≥80% predicted
• GOLD 2 - moderate: FEV1 50–79% predicted
• GOLD 3 - severe: FEV1 30–49% predicted
• GOLD 4 - very severe: FEV1 <30% predicted

The refined ABE assessment tool is provided in Figure 2.10 of the GOLD 2024 report (1).

The categories are defined via consideration of two specific features:

• exacerbation history and
• symptom score (either assessment of dyspnoea via mMRC OR assessment of symptoms via CAT)

Category A is defined by:

Category B is defined by:

Category E (in GOLD 2024, category C and D groups were merged into a single group) is defined by:

The combined COPD assessment allows patients with the same FEV1 (defined by the GOLD criteria) to be differentiated based on symptomatology, for example

• a subject with an FEV1 <30% with an mMRC of 2 and three exacerbations in the past year would be labelled GOLD grade 4, group E;
• whereas a subject with an FEV1 <30% with an mMRC of 1 and zero exacerbations in the past year would be labelled GOLD grade 4, group A

COPD assessment test

COPD assessment test (CAT) is an 8-item uni-dimensional measure of health status impairment in COPD.

• patients may score between 0-40
• measures the symptomatic impact of COPD but does not categorise patients into symptom severity groups for the purpose of treatment

CAT questionnaire can be found at http://www.catestonline.org/

St. George's Respiratory Questionnaire (SGRQ) is the most widely documented comprehensive measure which uses a score of >=25 as the cut-off point for considering regular treatment for symptoms. The equivalent cut-off point for CAT is 10

Reference:

1. Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2024. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease