| All patients | Comorbidity categories | p Value | |||
| 0 | 1 | ⩾2 | |||
| n | 2962 | 1443 | 1138 | 381 | |
| Age (y) | 71.1 (8.0) | 70.9 (8.3) | 71.3 (7.6) | 71.3 (7.7) | 0.429 |
| Sex (M/F) (n (%)) | 2150/812 (72/28) | 1060/383 (73/27) | 816/322 (71/29) | 274/107 (72/28) | 0.188 |
| Charlson Index | 1.52 (0.72) | 1.25 (0.56) | 1.79 (0.78) | 2.76 (0.68) | 0.001 |
| FEV1 (% predicted) | 49.3 (14.8) | 48.8 (14.9) | 50.0 (14.5) | 49.5 (15.4) | 0.128 |
| ATS-ERS* staging (n (%)) | |||||
| Mild | 2 (0.0) | 0 (0.0) | 2 (0.1) | 0 (0.0) | |
| Moderate | 1400 (47.2) | 648 (44.9) | 571 (50.1) | 181 (47.5) | |
| Severe | 1251 (42.2) | 640 (44.3) | 451 (39.6) | 160 (41.9) | |
| Very severe | 309 (10.4) | 155 (10.7) | 114 (10.0) | 40 (10.4) | |
| 6MWD (baseline) (m) | 335.2 (95.6) | 333.5 (96.2) | 344.2 (93.1) | 313.8 (98.4) | 0.001 |
| MRC grade (baseline) | 3.7 (0.92) | 3.7 (0.91) | 3.6 (0.91) | 3.9 (0.96) | 0.030 |
| SGRQ total score (baseline) | 39.5 (16.4) | 40.5 (16.8) | 39.8 (17.0) | 36.3 (12.9) | 0.414 |
Data are mean (SD).
*Mild COPD is defined as FEV1/FVC ratio⩽0.7 and FEV1%⩾80; moderate COPD as FEV1/FVC ratio⩽0.7 and FEV1% 50–80; severe COPD as FEV1/FVC ratio⩽0.7 and FEV1% 30–50; and very severe COPD FEV1/FVC ratio⩽0.7 and FEV1% <30.
6MWD, 6 min walking distance test; FEV1, forced expiratory volume in 1 s; MRC, Medical Research Council dyspnoea score; SGRQ, St. George’s Respiratory Questionnaire total score.