Comparison of discordant subsets
| Variable | Smokers (Fixed−LLN−) (n=4491) | Fixed+LLN−(n=548) | LLN+Fixed− (n=18) |
|---|---|---|---|
| Age | 57.1 (8.4) | 65.3 (7.9)** | 47.2 (2.0) |
| Sex (% women) | 2061 (46) | 162 (30)** | 16 (89) |
| BMI | 29.2 (6.0) | 28.7 (5.5)* | 28.1 (8.3) |
| Race (% black) | 1760 (39) | 64 (12)** | 15 (83) |
| Pack-years | 38.4 (20.9) | 50.0 (27.2)** | 35.7 (20.4) |
| Oxygen therapy at baseline (%) | 70 (1.6) | 25 (4.6)** | 0 (0) |
| FEV1 (litres) | 2.8 (0.7) | 2.4 (0.7) | 2.3 (0.6) |
| FEV1 % predicted | 92.5 (15.3) | 80.9 (14.9)** | 86.6 (12.1) |
| FVC (litres) | 3.5 (0.9) | 3.6 (1.0) | 3.3 (0.9) |
| FVC % predicted | 91.8 (14.9) | 90.4 (16.6)* | 99.3 (13.8) |
| FEV1/FVC | 0.78 (0.05) | 0.67 (0.02)** | 0.70 (0.01) |
| Response to bronchodilator (%) | 424 (9) | 105 (19)** | 5 (30) |
| TLC | 5.2 (1.3) | 5.9 (1.3)** | 4.5 (1.2) |
| FRC | 2.7 (0.7) | 3.3 (0.8)** | 2.5 (0.5) |
| 6MWD | 1469 (360) | 1433 (383) | 1423 (336) |
| MMRC | 0.8 (1.2) | 0.9 (1.3) | 1.7 (1.4) |
| BODE | 0.5 (1.0) | 0.7 (1.1)** | 1.4 (1.1) |
| Exacerbation frequency (per year) | 0.25 (1.1) | 0.33 (1.2)* | 0.08 (0.3) |
| LAA950insp | 1.9 (2.6) | 4.1 (4.3)** | 1.2 (1.3) |
| LAA856exp | 10.9 (9.7) | 19.8 (11.0)** | 7.5 (5.2) |
| Perc15 | −904.4 (25.4) | −920.5 (20.3)** | −889.9 (30.2) |
| Wall area (%) | 60.3 (3) | 60.8 (2.8)** | 62.9 (3.1) |
All values expressed as mean (SD).
*p<0.05; **p<0.001 for comparison between smokers (Fixed−LLN−) and fixed-only groups.
6MWD, 6 min walk distance; BMI, body mass index; BODE, body mass index, airflow obstruction, dyspnea and exercise capacity index; FEV1, forced expiratory volume in the first second; FRC, forced residual capacity; FVC, forced vital capacity; LAA856exp, percentage low attenuation area <856 Hounsfield units at end expiration; LAA950insp, percentage low attenuation area <950 Hounsfield units at end inspiration; MMRC, Modified Medical Research Council dyspnea scale; Perc15, percentage of voxels below the 15th percentile; TLC, total lung capacity.