Patient characteristics
| Total | Eosinophilic exacerbation | Non-eosinophilic exacerbation | p-value | |
| Subjects N | 152 | 51 | 101 | |
| Male n (%) | 71 (46.7) | 23 (45.1) | 48 (47.5) | 0.86 |
| Age years | 66.2±8.7 | 65.9±9.1 | 66.3±8.6 | 0.81 |
| Charlson Comorbidity Index | 2 (1–3) | 2 (1–3) | 2 (1–3) | 0.93 |
| Current smoker n (%) | 98 (64.5) | 32 (62.7) | 66 (65.3) | 0.56 |
| Tobacco smoke exposition pack-years | 40 (30–50) | 40 (30–50) | 40 (30–50) | 0.94 |
| FEV1 (post-bronchodilator) % pred | 35.52±14.07 | 35.89±11.59 | 35.35±15.18 | 0.85 |
| FEV1/FVC | 0.47±0.11 | 0.51 ±0.10 | 0.45±0.11 | <0.01 |
| Time since COPD diagnosis years | 7 (3–12) | 7 (2–11) | 6.5 (3.5–12.5) | 0.52 |
| Hospital admission due to COPD in the previous year n | 0 (0–1) | 0 (0–1) | 0 (0–1) | 0.67 |
| Admission corticosteroid use n (%) | 43 (37.0) | 17 (41.4) | 26 (34.7) | 0.55 |
| Baseline ICS use n (%) | 93 (61.2) | 29 (56.9) | 64 (63.4) | 0.38 |
| Baseline LAMA use n (%) | 118 (77.6) | 38 (74.5) | 80 (79.2) | 0.40 |
| Baseline LABA use n (%) | 117 (77.0) | 38 (74.5) | 79 (78.2) | 0.53 |
| Post-discharge ICS use n (%) | 105 (69.1) | 33 (64.7) | 72 (71.3) | 0.46 |
| WBC count on admission 109 cells·L−1 | 10.88±4.17 | 11.20±4.10 | 10.72±4.22 | 0.50 |
| Eosinophil count cells·µL−1 | 91 (19–261) | 362 (251–524) | 37 (4–89) | <0.0001 |
| Eosinophil count % of WBC | 0.80 (0.20–2.45) | 3.50 (2.40–5.20) | 0.40 (0.03–0.80) | <0.0001 |
| C-reactive protein mg·L−1 | 9.7 (3.0–27.0) | 7.8 (2.6–17.5) | 14.4 (4.2–37.9) | 0.02 |
| Antibiotic use n (%) | 116 (77.9) | 37 (72.5) | 79 (80.6) | 0.30 |
| Need for noninvasive ventilation n (%) | 24 (15.8) | 5 (9.8) | 19 (18.8) | 0.24 |
| Length of hospitalisation days | 7 (5–10) | 7 (5–12) | 7 (6–10) | 0.89 |
| Treatment failure n (%) | 31 (20.6) | 13 (26.0) | 18 (18.0) | 0.29 |
Data are presented as mean±sd, and compared with t-test, or median (interquartile range), and analysed with Mann–Whitney U-test, unless otherwise stated. Categorical variables were analysed with Fisher exact test. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; ICS: inhaled corticosteroid; LAMA: long-acting muscarinic antagonist; LABA: long-acting β2-agonist; WBC: white blood cell.