Table 1.
Baseline characteristics.
| Parameter | Young smokers without COPD (n = 47) | Older smokers without COPD (n = 24) | GOLD 1 (n = 32) | GOLD 2 (n = 23) | GOLD 3 (n = 27) | GOLD 4 (n = 13) |
|---|---|---|---|---|---|---|
| Age, years | 25.5 ± 7.7 | 55.3 ± 9.6 | 62.6 ± 8.0 | 63.8 ± 6.1 | 61.1 ± 6.3 | 56.2 ± 10.1 |
| Male sex, n(%) | 28 (59.6%) | 19 (79.2%) | 26 (81.3%) | 19 (82.6%) | 17 (63.0%) | 7 (53.8%) |
| BMI, kg/m2 | 23.4 ± 2.8 | 26.1 ± 3.7 | 26.8 ± 4.9 | 26.0 ± 3.6 | 23.9 ± 4.0 | 26.0 ± 7.5 |
| Packyears | 4.0 ± 5.3 | 29.0 ± 12.3 | 40.1 ± 17.9 | 33.8 ± 9.3 | 41.9 ± 18.0 | 35.5 ± 20.6 |
| Current smokers, n(%) | 40 (85.1%) | 22 (91.7%) | 20 (62.5%) | 14 (60.9%) | 13 (48.1%) | 3 (23.1%) |
| FEV1% predicted, % | 108.1 ± 8.8 | 111.9 ± 14.3 | 95.8 ± 10.3 | 63.9 ± 9.4 | 40.8 ± 5.6 | 23.5 ± 4.0 |
| FEV1/FVC, % | 84.8 ± 6.1 | 79.1 ± 6.1 | 63.2 ± 6.3 | 49.9 ± 9.1 | 36.9 ± 5.9 | 29.2 ± 5.6 |
| FEV1/VC, % | 85.1 ± 6.9 | 77.7 ± 5.4 | 60.1 ± 5.9 | 46.7 ± 8.3 | 34.2 ± 5.4 | 23.5 ± 3.8 |
| TLC, L | 7.1 ± 1.2 | 7.2 ± 1.1 | 8.0 ± 1.5 | 7.7 ± 1.4 | 7.7 ± 1.4 | 8.4 ± 1.4 |
| RV, L | 1.6 ± 0.5 | 2.3 ± 0.5 | 2.9 ± 0.8 | 3.4 ± 0.8 | 4.1 ± 0.9 | 5.3 ± 1.2 |
| RV/TLC, % | 23.3 ± 6.6 | 31.6 ± 5.9 | 36.2 ± 6.8 | 43.7 ± 7.3 | 53.1 ± 7.5 | 63.1 ± 6.1 |
| TLCOc, mmol/min/kPa | 10.6 ± 2.3 | 8.9 ± 1.6 | 7.3 ± 2.4 | 6.1 ± 2.0 | 3.9 ± 1.7 | 3.5 ± 2.2 |
| VA, L | 6.4 ± 1.1 | 6.3 ± 1.0 | 6.8 ± 1.1 | 5.9 ± 1.1 | 5.4 ± 1.0 | 4.7 ± 0.7 |
| KCO, mmol/min/kPa/L | 1.7 ± 0.3 | 1.4 ± 0.2 | 1.1 ± 0.3 | 1.0 ± 0.3 | 0.7 ± 0.2 | 0.7 ± 0.3 |
| 6MWD, m | – | – | 531 ± 80 | 540 ± 85 | 450 ± 89 | 329 ± 117 |
| MRC dyspnea scale | 0.6 ± 0.5 | 0.7 ± 0.6 | 1.3 ± 0.7 | 1.8 ± 0.9 | 2.5 ± 1.3 | 3.9 ± 1.0 |
| BODE index | – | – | 0.1 ± 0.4 | 0.8 ± 1.0 | 3.1 ± 1.5 | 6.0 ± 1.7 |
| SGRQ score | – | – | 21.0 ± 12.2 | 30.4 ± 14.2 | 38.9 ± 13.3 | 49.7 ± 15.0 |
| No. of exacerbations | – | – | 0.6 ± 1.9 | 0.4 ± 0.8 | 1.3 ± 2.1 | 1.5 ± 1.6 |
| No. of antibiotic courses | 0.2 ± 0.6 | 0.1 ± 0.4 | 0.2 ± 0.4 | 0.7 ± 1.0 | 1.5 ± 2.0 | 1.7 ± 1.4 |
| No. of prednisolone courses | 0 | 0 ± 0.2 | 0.2 ± 0.5 | 0.4 ± 0.8 | 1.4 ± 2.2 | 1.8 ± 1.4 |
| PRMNormal, % | 77.0 (66.8–80.9) | 72.7 (67.8–78.1) | 51.4 (45.4–59.1) | 42.8 (33.1–46.9) | 30.2 (22.7–34.1) | 18.7 (12.3–29.8) |
| PRMEmph, % | 0.9 (0.1–1.1) | 1.4 (0.3–1.5) | 3.7 (1.9–7.8) | 7.4 (4.0–14.3) | 14.7 (10.1–30.2) | 26.2 (17.8–46.4) |
| PRMfSAD, % | 4.1 (1.3–7.4) | 9.8 (4.6–14.1) | 25.4 (19.1–31.2) | 31.2 (25.8–37.4) | 35.1 (31.8–41.7) | 37.1 (31.0–37.5) |
COPD: chronic obstructive pulmonary disease; FEV1: forced expiratory volume in one second; FVC: forced vital capacity; VC: vital capacity; TLC: total lung capacity; RV: residual volume; TLCOc: pulmonary diffusion capacity for carbon monoxide, corrected for hemoglobin count; VA: alveolar volume; KCO: transfer coefficient for carbon monoxide; BMI: body mass index; 6MWD: six minute walking distance; MRC: Medical Research Council; SGRQ: St. George’s respiratory questionnaire; PRMNormal: extend of normal lung tissue; PRMEmph: extend of emphysema; PRMfSAD: extend of small airway disease.