| All(n = 35) | Theophylline(n = 16) | Standard therapy(n = 19) | |
| Age (years) | 67.6 (1.3) | 66.7 (1.7) | 68.2 (2.1) |
| Gender (M/F) | 35/0 | 16/0 | 19/0 |
| Smoking (pack-years) | 58.6 (4.3) | 62.9 (6.9) | 54.1 (6.4) |
| Active smoking, n (%) | 15 (42%) | 8 (50%) | 7 (37%) |
| Charlson index | 1.83 (0.2) | 1.77 (0.3) | 1.88 (0.2) |
| FEV1 (l) | 1.03 (0.1) | 0.99 (0.1) | 1.11 (0.1) |
| FEV1 (%) | 38.4 (2.1) | 39.2 (3.8) | 37.7 (1.9) |
| FEV1/FVC (%) | 46.39 (1.9) | 45.34 (3.3) | 47.89 (2.7) |
| Salbutamol reversibility (%) | 5.17 (1.3) | 7.33 (1.6) | 3.89 (1.6) |
| ICS, n (%) | 21 (60%) | 11 (68%) | 10 (53%) |
| Pao2 (mm Hg) | 56.4 (1.6) | 53.7 (2.4) | 58.6 (1.7) |
| Paco2 (mm Hg) | 45.6 (1.7) | 48.4 (2.5) | 42.7 (2.2) |
Values are mean (SEM) unless indicated otherwise.
FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; ICS, inhaled corticosteroids; Pao2, Paco2, arterial oxygen and carbon dioxide tensions.