Table 1. Results of pulmonary function tests, blood gas analysis, and 6MWT.
| Parameters | All subjects (n=130) | Stage I (n=11) | Stage II (n=69) | Stage III (n=11) | Stage IV (n=39) | Adjusted P |
|---|---|---|---|---|---|---|
| Pulmonary function tests | ||||||
| FEV1 (% pred) | 80 [31] | 97 [19] | 83 [25] | 90 [11] | 66 [30]a,b,c | 0.00001 |
| FVC (% pred) | 92 [24] | 98 [26] | 96 [21] | 102 [19] | 79 [32]a,b,c | 0.001 |
| TLC (% pred) | 90 [19] | 88 [14] | 90 [21] | 93 [29] | 88 [24] | 0.644 |
| FEV1/FVC (%) | 75 [15] | 80 [8] | 75 [15] | 79 [12] | 71 [24]a,b,c | 0.011 |
| DLco (% pred) | 71 [25] | 82 [18] | 76 [23] | 73 [17] | 55 [23]a,b,c | 0.00001 |
| Kco (% pred) | 91 [25] | 94 [21] | 94 [22] | 86 [12] | 77 [34]a,b | 0.0004 |
| Blood gases | ||||||
| Resting PaO2 (mmHg) | 90 [12] | 89 [9] | 90 [14] | 91 [3] | 88 [13] | 0.644 |
| Resting AaDO2 (mmHg) | 16 [12] | 11 [13] | 16 [8] | 14 [8] | 23 [12] | 0.15 |
| VO2 peak (mL/kg/min) | 20.2 [9] | 23 [9] | 21.3 [8] | 21.3 [11] | 16.9 [6]a,b | 0.021 |
| VO2 peak (% pred) | 69 [9] | 74 [31] | 74 [28] | 70 [36] | 59 [26]a,b,c | 0.042 |
| Peak PaO2 (mmHg) | 84 [25] | 97 [17] | 87 [21] | 94 [12] | 69 [22]a,b,c | 0.011 |
| Peak AaDO2 (mmHg) | 29 [19] | 15 [23] | 27 [13] | 24 [15] | 44 [23]a,b,c | 0.011 |
| 6MWT | ||||||
| Distance (m) | 450 [100] | 460 [110] | 450 [100] | 490 [100] | 460 [125] | 0.644 |
| Resting SpO2 (%) | 96 [1] | 96 [2] | 97 [1] | 96 [1] | 96 [3] | 0.644 |
| Nadir SpO2 (%) | 94 [6] | 95 [4] | 94 [3] | 96 [3] | 89 [12]a,b,c | 3×10–8 |
| ∆SpO2-6MWT (%) | 2 [4] | 2 [2] | 2 [3] | 0 [2]d | 4 [9]b,c | 0.011 |
Data are presented as the median and [interquartile range]. a, P<0.05 between stages I and IV; b, P<0.05 between stages II and IV; c, P<0.05 between stages III and IV; d, P<0.05 between stages II and III. 6MWT, 6-minute walk test; ∆SpO2, oxygen desaturation [(resting – nadir) SpO2]; AaDO2, alveolar-to-arterial oxygen pressure difference; DLco, diffusing capacity of the lung for carbon monoxide; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; Kco, carbon monoxide transfer coefficient; PaO2, partial pressure of oxygen; pred, predicted; TLC, total lung capacity; VO2 peak, peak oxygen uptake.