Patients characteristics at baseline
| Characteristics | Total COPD patients | Cardiovascular indication for β-blockers | No cardiovascular indication for β-blockers | p-value |
| Patients n | 1312 | 755 | 557 | |
| Age years | 69.7±9.2 | 70.4±8.8 | 68.8±9.7 | 0.002 |
| Male sex | 750 (57.2) | 438 (58.0) | 312 (56.0) | 0.470 |
| Ever smokers | 1104 (84.1) | 632 (83.7) | 472 (84.7) | 0.450 |
| BMI kg·m−2 | 26.0 (23.7–28.9) | 26.5 (24.1–29.4) | 25.5 (23.0–28.0) | <0.001 |
| Heart failure | 94 (7.2) | 94 (12.5) | NA | NA |
| Coronary heart disease | 156 (11.9) | 156 (20.7) | NA | NA |
| Atrial fibrillation | 31 (2.4) | 31 (4.1) | NA | NA |
| Hypertension# | 685 (52.2) | 685 (90.7) | NA | NA |
| Diabetes¶ | 105 (8.0) | 81 (10.7) | 24 (4.3) | <0.001 |
Data are presented as mean±sd, n (%) or median (interquartile range), unless otherwise stated. Cardiovascular indication for β-blockers use was defined as a history of hypertension, coronary heart disease, atrial fibrillation and/or heart failure at baseline. BMI: body mass index; NA: not applicable. #: data were missing on hypertension in 218 subjects; ¶: diabetes mellitus was defined as a fasting serum glucose concentration of ≥7.0 mmol·L−1 or a non-fasting serum glucose concentration of ≥11.1 mmol·L−1 or the use of blood glucose-lowering medications [40].