Characteristics of the studied patients
| Variable | Value | Intercountry range |
| Male sex | 10 865 (67.8) | 47.3–86.0 |
| Age years | 70.7±10.7 | 63.4–72.7 |
| Current smokers | 5012 (31.3) | 15.4–46.8 |
| Tobacco history pack-years | 47.2±31.2 | 29.8–70.8 |
| Comorbidity | ||
| Charlson Comorbidity Index score | 2.4±1.6 | 1.7–3.1 |
| Cardiovascular disease | 6491 (40.5) | 32.4–71.4 |
| Diabetes | 3181 (19.9) | 11.9–27.5 |
| Neoplasms | 1950 (12.2) | 2.6–18.9 |
| Body mass index kg·m−2 | 26.6±6.4 | 25.0–28.5 |
| Admissions in previous 12 months | 1.2 (1.8) | 0.4–1.8 |
| Spirometry | ||
| FVC % predicted | 65.4±20.3 | 45.2–74.9 |
| FEV1 % predicted | 44.0±17.4 | 38.9–56.1 |
| Previous GOLD spirometric classification | ||
| No spirometry available | 6512±40.7 | 9.9–53.6 |
| Spirometry with no obstruction | 1226±7.7 | 3.2–34.0 |
| Mild | 195±1.2 | 0–3.0 |
| Moderate | 2175±13.6 | 2.7–31.0 |
| Severe | 3737±23.3 | 11.6–34.9 |
| Very severe | 2098±13.1 | 4.8–23.8 |
| Missing | 75±0.5 | 0–2.7 |
| Dyspnoea increase | 15 409 (96.2) | 92.5–100 |
| Sputum increase | 10 373 (64.8) | 49.2–79.0 |
| Sputum colour change | 8134 (50.8) | 36.9–63.3 |
| pH | 7.39±0.07 | 7.37–7.41 |
| PaCO2 kPa | 6.4±2.1 | 5.7–7.0 |
| PaO2 kPa | 8.6±3.4 | 7.3–10.8 |
| Chest radiography | ||
| Normal or COPD-like findings | 8051 (50.3) | 33.0–55.5 |
| Consolidation | 2969 (18.5) | 8.9–32.6 |
| Other findings | 4752 (29.7) | 16.7–58.0 |
Data are presented as n (%) or mean±sd, unless otherwise stated. FVC: forced vital capacity; FEV1: forced expiratory volume in 1 s; GOLD: Global Initiative for Chronic Obstructive Lung Disease; PaCO2: arterial carbon dioxide tension; PaO2: arterial oxygen tension; COPD: chronic obstructive pulmonary disease.