ICCs for the intercept-only model and adjusted model for the change, end and MCID scores for each measure of the total population in practices that provided ≥10 patients
| Intercept-only model | Adjusted model | |
| 6MWT end score | 0.08 | 0.17# |
| 6MWT change score | 0.00 | 0.01# |
| 6MWT MCID improvement¶ | 0.03 | 0.04# |
| 6MWT MCID deterioration¶ | 0.06 | 0.06 |
| CCQ end score | 0.11 | 0.20# |
| CCQ change score | 0.06 | 0.09# |
| CCQ MCID improvement+ | 0.05 | 0.07# |
| CCQ MCID deterioration+ | 0.03 | 0.05# |
| GPE-DV end score | 0.14 | 0.15# |
| MRC end score | 0.08 | 0.12# |
| MRC change score | 0.23 | 0.34# |
6MWT: 6-min walk test; CCQ: Clinical COPD Questionnaire; GPE-DV: Global Perceived Effect – Dutch Version; HHD: hand-held dynamometer; ICC: intraclass correlation coefficient; MCID: minimal clinically important difference; MRC: Medical Research Council Dyspnoea Scale; N.A: not applicable. #Increase in the ICC compared with the intercept-only model following the adjustment for the case-mix variables age, gender and baseline score of the measure. ¶For the multilevel analysis of the 6MWT, we used an MCID of ± ≥30 m [33]. +For the multilevel analysis of the CCQ, we used an MCID of ± ≥0.4 points [34].