Background The COPD assessment test (CAT) was introduced last year.1 It is a questionnaire that contains eight questions covering domains relating to the impact of COPD symptoms. It is a self completion questionnaire and does not require scoring software. Scores of 0–10, 11–20, 21–30, 31–40 represent mild, moderate, severe or very severe clinical impact. In cross-sectional studies it has similar scaling properties to the SGRQ, so that 1 point in the CAT is equivalent to approximately 2.5 points on the SGRQ. It is not known how the CAT score performs in the context of pulmonary rehabilitation (PR).
Methods We prospectively studied the introduction of the CAT score as an assessment tool in several pulmonary rehabilitation programs across London, where it was used alongside a range of other outcome measures in different programs including the SGRQ, CCQ, HAD score, MRC dyspnoea score and several different walking tests. Primary outcome was a comparison of change in CAT score against an anchor question used to assess overall response, scored 1 “I feel much better” 2 “I feel a little better”, 3 “I feel no different”, 4 “I feel a little worse”, 5 “I feel much worse”.
Results Data were available for 172 COPD patients, mean(SD) age 69.6(9.3) years, FEV1 51.9(18.9)% predicted, MRC dyspnoea score 3.0(0.9), CAT score 20.0(7.5) who attended five different programs. Mean improvement in CAT score after PR was 2.8(5.8) points. In those scoring “much better” (n=108) CAT fell by 3.7(6.1) points and by 1.2(4.8) in those who felt “a little better” (n=56) (p=0.01). In those scoring 3 or 4 on the anchor question (grouped together as n=8) change in CAT was −0.6(3.5).
Conclusion The CAT score improves in response to pulmonary rehabilitation and more so in those who report a greater overall improvement. Further accrual is underway to allow comparison of changes in CAT to other outcome measures.
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Funding The NIHR Respiratory Biomedical Research Unit Royal Brompton & Harefield NHS Foundation Trust and Imperial College.