Health status of COPD patients undergoing pulmonary rehabilitation : a comparative responsiveness of the CAT and SGRQ

Abstract

The St. George’s Respiratory Questionnaire (SGRQ) and chronic obstructive pulmonary disease (COPD) assessment test (CAT) are the measures used to assess health status. This study aims to examine the responsiveness of these tools by severity of dyspnoea category in patients with COPD. Forty-nine COPD patients who underwent a 12-week pulmonary rehabilitation (PR) programme were assessed at baseline, 12 weeks and at 28-week follow-up. Patients were categorized into two groups by severity of dyspnoea category (i.e. mild to moderate (modified Medical Research Council (mMRC) 1–2) and severe to very severe (mMRC 3–4)) using the mMRC dyspnoea scale. Effect size (ES) was computed as estimates of responsiveness. The SGRQ demonstrated greater responsiveness by total sample (SGRQ, ES = 0.87; CAT, ES = 0.75) and for the mMRC 3–4 category (SGRQ, ES = 0.91; CAT, ES = 0.76) on completion of PR. At 28-week follow-up, overall comparable responsiveness of the CAT and SGRQ was identified by total sample (SGRQ, ES = 0.75; CAT, ES = 0.74) and by severity of dyspnoea category. The symptom, impact and activity domains of the SGRQ showed good responsiveness, with greater ESs obtained overall for the mMRC 3–4 category. On completion of PR, the SGRQ demonstrates a greater responsiveness with COPD patients, especially in relation to the mMRC 3–4 category, while both the CAT and SGRQ show comparable responsiveness on follow-up.