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.

CCQ score category
Score difference



Mean
95% confidence interval
p value

Death (n = 25) or survival (n = 143)




Total
-0.80
-1.23, -0.37
<0.001*
Symptoms
-0.62
-1.13, -0.12
0.015*
Function
-1.32
-1.90, -0.74
<0.001*
Mental
0.5§

0.211

Rehospitalization (n = 56) or not (n = 112)




Total
-0.18
-0.52, 0.16
0.290
Symptoms
-0.07
-0.46–0.31
0.706
Function
-0.47
-0.93, -0.007
0.047*
Mental


0.505

Death/rehospitalization (n = 70) versus survival/no rehospitalization (n = 98)




Total
-0.39
-0.71, -0.07
0.017*
Symptoms
-0.27
-0.63, 0.10
0.153
Function
-0.77
-1.19, -0.34
0.001*
Mental


0.987

* Statistically significant (2-tailed): p < 0.05. § Difference in median scores

COPD = chronic obstructive pulmonary disease.

Kocks et al. Respiratory Research 2006 7:62   doi:10.1186/1465-9921-7-62