Table 1

Minimal Clinically Important Difference (MCID) for the Clinical COPD Questionnaire (CCQ) by patient referencing. Differences between CCQ scores for Days 1 and 2 grouped according to Global Rating of Change (GRC) as scored by patients on a scale of -7 to 7. Note that paired-sample t-tests were used for total CCQ scores and for symptom and functional domains; Wilcoxon signed rank test was used for the mental domain.

CCQ score category
Score difference: Day 1 minus Day 2



Mean ± SD
95% confidence interval
p value

GRC +1 (n = 3)




Total
0.30 ± 0.30
-0.45, 1.05
0.225
Symptoms
-0.25 ± 1.64
-4.32, 3.82
0.816
Function
1.17 ± 0.80
-0.83, 3.16
0.128
Mental
-0.5§

0.157

GRC +2 to +3 (n = 15)




Total
0.40 ± 0.90
-0.09, 0.91
0.098
Symptoms
0.70 ± 1.09
0.98, 1.30
0.026*
Function
0.17 ± 1.37
-0.93, 0.59
0.645
Mental
1.0§

0.007*

GRC +4 to +5 (n = 14)




Total
1.31 ± 1.09
0.69, 1.94
0.001*
Symptoms
1.13 ± 1.52
0.25, 2.0
0.016*
Function
1.48 ± 1.25
0.76, 2.20
0.001*
Mental
0.5§

0.018*

GRC +6 to +7 (n = 2)




Total
1.95 ± 0.07
1.31, 2.59
0.016*
Symptoms
2.75 ± 1.77
-13.13, 18.63
0.272
Function
1.50 ± 1.06
-8.03, 11.03
0.295
Mental
1.25§

0.317

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

COPD = chronic obstructive pulmonary disease; SD = standard deviation.

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