Subjects without COPD (noCOPD) according to maximum mid-expiratory flow (MMEF) above and below 80%
| NoCOPD MMEF <80% | NoCOPD MMEF >80% | p-value | |
| Subjects n | 135 | 74 | |
| Age years | 54.05±11.05 | 47.82±9.31 | 0.01 |
| BMI kg·m−2 | 28.75±4.99 | 27.18±4.95 | 0.01 |
| Smoking history pack-years | 45.17±25.57 | 38.10±20.92 | 0.048 |
| Active smokers, n (%) | 61 (45) | 33 (45) | ns |
| CAT score | 9.42±6.84 | 8.24±6.94 | ns |
| Subjects with CAT ≥10, n (%) | 47 (35) | 23 (31) | ns |
| Distance at 6MWT m | 459±109 | 519±114 | 0.01 |
| Number of total exacerbations per year | 0.56±1.12 | 0.36±0.91 | 0.04 |
| Subjects with CB n (%) | 42 (31) | 14 (19) | 0.04 |
| Subjects with mMRC ≥2, n (%) | 49 (36) | 22 (30) | ns |
| mMRC score | 1.23±1.19 | 0.85±1.15 | 0.01 |
| Subjects with DLCO <80% | 56 (41) | 24 (32) | ns |
| DLCO % pred | 84± 18 | 89±17 | ns |
| FEV1 % pred | 90.74±12.74 | 105.11±12.74 | 0.0001 |
| FEV1/FVC % | 76.39±3.9 | 82.31±3.89 | 0.0001 |
| Subjects who develop COPD at V3, n (%) | 28(21) | 2(2.7) | 0.001 |
Data are presented as n (%), and mean±sd. p-value refers to Mann–Whitney test or χ2 test. ns: nonsignificant; BMI: body mass index; CAT: COPD Assessment Test; 6MWT: 6-min walk test; CB: chronic bronchitis; mMRC: modified Medical Research Council; DLCO: diffusing capacity of the lung for carbon monoxide; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; V3: third visit..