Table 3 Minimal Clinically Important Difference (MCID) for the Clinical COPD Questionnaire (CCQ) by criterion referencing. Differences between baseline (Day 42) CCQ scores are grouped according to major health events during 12-month follow-up. Unpaired-sample t-tests were used for total CCQ scores and for symptom and functional domains, with equal variances assumed; the Mann-Whitney U test was used for the mental domain.

From: Health status measurement in COPD: the minimal clinically important difference of the clinical COPD questionnaire