Main demographic, clinical and functional characteristics of participants
| Controls | COPD FE | COPD IE | |
|---|---|---|---|
| N=10 | N=14 | N=20 | |
| Demographic and clinical characteristics | |||
| Age. years | 63±6 | 65±9 | 65±10 |
| Males, n (%) | 8 (80%) | 12 (86%) | 17 (85%) |
| BMI, kg/m2 | 29±4 | 27±5 | 27±7 |
| Current smokers, n (%) | 0 | 4 (29%) | 7 (35%) |
| Former smokers, n (%) | 4 (40%) | 10 (71%) | 13 (65%) |
| Cumulative smoking exposure (packs/year) | 25±11 | 52±25 | 55±34 |
| LAMA, n (%) | – | 14 (100%) | 17 (85%) |
| LABA, n (%) | – | 13 (93%) | 16 (80%) |
| ICS, n (%) | – | 13 (93%) | 15 (75%) |
| Lung function | |||
| FEV1/FVC, % | 0.79±0.42 | 0.39±0.10 | 0.43±0.19 |
| FEV1, % predicted | 100±14 | 39±13 | 45±16 |
| GOLD II, n (%) | – | 3 (21%) | 10 (50%) |
| GOLD III, n (%) | – | 6 (43%) | 6 (30%) |
| GOLD IV, n (%) | – | 5 (36%) | 4 (20%) |
| IC, % predicted | – | 64±12 | 61±12 |
| TLC, % predicted | – | 117±12 | 108±15 |
| IC/TLC, % | – | 0.55±0.12 | 0.57±0.13 |
| FRC, % predicted | – | 162±29 | 149±33 |
| RV, % predicted | – | 192±47 | 160±50 |
| DLCO, % predicted | – | 49±13 | 50±17 |
| PaO2, mm Hg | – | 73.83±7.92 | 73.48±8.61 |
| PaCO2, mm Hg | – | 39.06±3.02 | 40.36±5.09 |
| Respiratory muscle function | |||
| MIP, % predicted | 89.60±24.79 | 72.60±25.47 | 68.83±23.45 |
| MEP, % predicted | 86.40±16.95 | 70.64±17.89 | 69.54±21.86 |
Results are expressed as mean±SD.
BMI, body mass index; DLCO, single-breath diffusing capacity for carbon monoxide; FE, frequent exacerbation; FRC, functional residual capacity; IC, inspiratory capacity; ICS, inhaled corticosteroids; IE, infrequent exacerbation; LABA, long-acting β2-agonists; LAMA, long-acting muscarinic antagonists; MEP, maximal expiratory pressure (although they were not measured in all the subjects); MIP, maximal inspiratory pressure; RV, residual volume; TLC, total lung volume.