| Baseline characteristic | Study population (n = 1007) |
| Age (y) | 66 (50–78) |
| Gender (% male) | 49.7 |
| Duration of admission (days) | 5 (3–11) |
| Chronic cardiac failure (%) | 20 |
| Cerebrovascular disease (%) | 11.6 |
| Chronic renal failure (%) | 6 |
| Diabetes mellitus (%) | 10.1 |
| COPD (%) | 20.6 |
| Other chronic lung diseases (%) | 3.6 |
| Current smokers (%) | 34.2 |
| Ex-smokers (%) | 21.4 |
| Non-smokers (%) | 44.4 |
COPD, chronic obstructive pulmonary disease.