Responsiveness and MCID Estimates for CAT, CCQ, and HADS in Patients With COPD Undergoing Pulmonary Rehabilitation: A Prospective Analysis

Abstract

Objectives: Pulmonary rehabilitation enhances health status and mood status in patients with chronic obstructive pulmonary disease (COPD). The aim was to determine the responsiveness of St. George's Respiratory Questionnaire (SGRQ), COPD Assessment Test (CAT), COPD Clinical Questionnaire (CCQ), and Hospital Anxiety and Depression Scale (HADS) to pulmonary rehabilitation in patients with COPD, and estimate minimum clinically important differences (MCIDs) for CAT, CCQ, and HADS.

Design: A prospective analysis. MCIDs were estimated with anchor-based (anchor: SGRQ) and distribution-based methods. Newly estimated MCIDs were compared to known MCID estimates from a systematic literature search.

Setting: Newly estimated MCIDs were calculated in patients treated in pulmonary rehabilitation.

Participants: A subsample of 419 individuals with COPD (55.4% male, mean age 64.3 ± 8.8 years) were included from the Chance study.

Measurements: Health status was measured with SGRQ, CAT, and CCQ, before and after pulmonary rehabilitation. Mood status was assessed using HADS.

Results: 419 patients with COPD (forced expiratory volume in the first second 37.3% ± 12.1% predicted) completed pulmonary rehabilitation. SGRQ (-9.1 ± 14.0 points), CAT (-3.0 ± 6.8 points), CCQ (-0.6 ± 0.9 points), HADS-Anxiety (-1.7 ± 3.7 points), and HADS-Depression (-2.1 ± 3.7 points) improved significantly. New MCIDs were estimated for CAT (range: -3.8 to -1.0 points), CCQ (range: -0.8 to -0.2 points), HADS-Anxiety (range: -2.0 to -1.1 points), and HADS-Depression (range: -1.8 to -1.4 points).

Conclusions: The SGRQ, CAT, CCQ, and HADS are responsive to pulmonary rehabilitation in patients with COPD. We propose MCID estimates ranging between -3.0 and -2.0 points for CAT; -0.5 and -0.3 points for CCQ, -1.8 and -1.3 points for HADS-Anxiety, and -1.7 and -1.5 points for HADS-Depression.

Keywords: COPD; clinical significance; health status; health-related quality of life; pulmonary rehabilitation.