Univariate correlates of change in CAT score
| Variable | Correlation coefficient | No. of observations | p Value |
| ΔCRQ total | −0.41 | 195 | <0.001 |
| ΔSGRQ total | 0.36 | 38 | 0.03 |
| ΔCCQ | 0.13 | 57 | 0.034 |
| ΔHAD anxiety | 0.15 | 210 | 0.03 |
| ΔHAD depression | 0.17 | 211 | 0.01 |
| ΔISWT | −0.19 | 191 | 0.008 |
| Δ6MWT | 0.31 | 68 | 0.01 |
| ΔlnESWT | −0.19 | 27 | 0.35 |
| ΔMRC | 0.20 | 130 | 0.02 |
CAT, COPD assessment test; CCQ, Clinical COPD Questionnaire; COPD, chronic obstructive pulmonary disease; CRQ, chronic respiratory questionnaire; HAD, Hospital Anxiety and Depression score; ISWT, incremental shuttle walk test; lnESWT, log-transformed endurance shuttle walk test; MRC, Medical Research Council dyspnoea score; 6MWT, 6 min walk test; SGRQ, St George's Respiratory Questionnaire.