Mean (SD) baseline characteristics of study patients (n = 304)
| All patients(n = 304) | Group A(n = 163, 53.6%) | Group B(n = 105, 34.5%) | Group C(n = 36, 11.8%) | p value | |
|---|---|---|---|---|---|
| BMI, body mass index; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; Pao2, Paco2, arterial oxygen and carbon dioxide tensions. | |||||
| Group A, no acute exacerbations of COPD; group B, 1–2 acute exacerbations of COPD (emergency visits or hospital admissions); group C, ⩾3 acute exacerbations of COPD. | |||||
| Age (years) | 71 (9) | 69 (10) | 72 (7) | 71 (9) | 0.001 |
| BMI (kg/m2) | 28.3 (5.1) | 28.8 (5.4) | 27.7 (4.7) | 27.7 (4.1) | 0.350 |
| Co-morbidity index | 0.95 (1.34) | 0.90 (1.30) | 0.92 (1.21) | 1.23 (1.82) | 0.422 |
| Co-morbidity, n (%) | 0.765 | ||||
| 0 | 145 (47.7%) | 80 (48.8%) | 48 (46.2%) | 17 (47.2%) | |
| 1 | 91 (29.9%) | 47 (28.6%) | 35 (33.6%) | 9 (25.0%) | |
| ⩾2 | 68 (22.4%) | 37 (22.6%) | 21 (20.2%) | 10 (27.8%) | |
| FEV1 (l) | 1.18 (0.64) | 1.29 (0.76) | 1.11 (0.45) | 0.88 (0.33) | 0.002 |
| FEV1 (% predicted) | 46.4 (17.2) | 49.2 (16.6) | 45.9 (17.6) | 34.5 (13.6) | <0.001 |
| GOLD classification, n (%) | <0.001 | ||||
| Stage I | 20 (6.6%) | 15 (9.2%) | 5 (4.8%) | – | |
| Stage II | 109 (35.9%) | 66 (40.5%) | 38 (36.2%) | 5 (13.9%) | |
| Stage III | 102 (33.6%) | 57 (35.0%) | 33 (31.4%) | 12 (33.3%) | |
| Stage IV | 73 (24.0%) | 25 (15.3%) | 29 (27.6%) | 19 (52.8%) | |
| FVC (l) | 2.22 (0.67) | 2.34 (0.72) | 2.12 (0.62) | 1.93 (0.62) | 0.002 |
| FVC (% predicted) | 69.4 (19.1) | 72.0 (19.3) | 68.0 (18.7) | 61.1 (17.3) | 0.010 |
| Pao2 (kPa) | 8.8 (1.6) | 9.1 (1.5) | 8.6 (1.5) | 8.0 (1.6) | <0.001 |
| Paco2 (kPa) | 5.8 (1.0) | 5.7 (0.8) | 5.9 (1.0) | 6.2 (1.4) | 0.019 |