Baseline clinical characteristics of COPD patients with acute exacerbation within the study cohort (n=358 patients)
| Characteristics | Missing data n (%) | AECOPD patients (n=358) | |
| Male (n, %) | 0 (0) | 309 | −86.3 |
| Age ≥80 years (n, %) | 0 (0) | 131 | −36.6 |
| Age, years, mean (±SD) | 0 (0) | 74 | ±11.1 |
| Body mass index, kg/m2, mean (±SD) | 171 (47.8) | 20.4 | ±4.2 |
| Smoking status | |||
| Never smoker (n, %) | 0 (0) | 20 | −5.6 |
| Ex-smoker (n, %) | 292 | −81.6 | |
| Active smoker (n, %) | 46 | −12.9 | |
| Underlying diseases (n, %) | |||
| Present (any) | 0 (0) | 296 | −82.7 |
| Hypertension | 0 (0) | 145 | −40.5 |
| Diabetes mellitus | 0 (0) | 44 | −12.3 |
| Dyslipidemia | 0 (0) | 48 | −13.4 |
| Ischaemic heart disease | 0 (0) | 36 | −10.1 |
| Atrial fibrillation | 0 (0) | 20 | −5.6 |
| Left ventricular dysfunction | 0 (0) | 6 | −1.7 |
| Chronic kidney disease | 0 (0) | 27 | −7.5 |
| Cerebrovascular disease | 0 (0) | 27 | −7.5 |
| COPD status | |||
| Spirometry done (n, %) | 0 (0) | 82 | −22.9 |
| FEV1, % predicted, median (IQR) | 276 (77.1) | 38 | 29.0 to 57.0 |
| FVC, % predicted, median (IQR) | 277 (77.4) | 64 | 51.0 to 84.0 |
| FEV1/FVC ratio, mean (±SD) | 276 (77.1) | 0.5 | ±0.1 |
| GOLD severity of airflow limitation (n, %) | |||
| I: FEV1 ≥80% predicted | 276 (77.1) | 6 | −1.7 |
| II: FEV1 50–79% predicted | 20 | −5.6 | |
| III: FEV1 30–49% predicted | 33 | −9.2 | |
| IV: FEV1 <30% predicted | 23 | −6.4 | |
| Long-term oxygen therapy, (n, %) | 0 (0) | 26 | −7.3 |
| Cor pulmonale (n, %) | 0 (0) | 12 | −3.4 |
| Number of events in previous year | |||
| Hospitalisation, median (IQR) | 25 (7.0) | 0 | 0 to 1 |
| ED visit, median (IQR) | 37 (10.3) | 0 | 0 to 2 |
| Influenza vaccination | 0 (0) | 23 | −6.4 |
AECOPD, Acute exacerbation of chronic obstructive pulmonary disease; COPD, chronic obstructive pulmonary disease; ED, emergency department; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity.