Main clinical characteristics of the exacerbations of chronic obstructive pulmonary disease (ECOPD) subgroups divided according to frequency of ECOPD in the year after the index event
| Nonfrequent ECOPD | Frequent ECOPD | p-value | |
| Subjects | 197 | 121 | |
| Age (mean) | 72.2 | 71.9 | 0.81 |
| Males | 64.5 (127) | 66.1 (80) | 0.74 |
| BMI kg·m−2 (mean) | 28.9 | 27.8 | 0.18 |
| Pack-years (median) | 50 | 55 | 0.082 |
| COPD pattern | |||
| Chronic bronchitis | 60.1 (119) | 62.8 (76) | 0.658 |
| Emphysema | 40.9 (81) | 57 (69) | 0.007 |
| Bronchiectasis | 18.7 (37) | 22.3 (27) | 0.342 |
Data are presented as n or % (n), unless otherwise stated. BMI: body mass index.