TABLE 4.
Severity of airway obstruction according to different staging systems
| GOLD [2] | ATS/ERS [24] | Quanjer [25] | ||||
| Subjects | Subjects at stage with respiratory symptoms | Subjects | Subjects at stage with respiratory symptoms | Subjects | Subjects at stage with respiratory symptoms | |
| Subjects n | 1854 | 576 | 576 | |||
| Mild | 1045 (56) | 283 (27) | 292 (51) | 98 (34) | 307 (53) | 104 (34) |
| Moderate | 704 (38) | 352 (50) | 125 (22) | 70 (56) | 90 (16) | 53 (59) |
| Moderately severe | NA | NA | 73 (13) | 47 (64) | 90 (16) | 59 (66) |
| Severe | 90 (4.9) | 76 (85) | 59 (10) | 48 (81) | 69 (12) | 54 (78) |
| Very severe | 15 (1) | 13 (87) | 27 (5) | 26 (96) | 20 (3) | 19 (95) |
Data are presented as n (%), unless otherwise stated. GOLD: Global Initiative for Chronic Obstructive Pulmonary Disease; ATS: American Thoracic Society; ERS: European Respiratory Society; NA: not applicable.