Diffusing capacity of nitric oxide in chronic obstructive pulmonary disease(COPD) and healthy subjects calculated by different methods
| Linear 2 | Nonlinear | Mixed 1 | Mixed 2 | |
| COPD smokers | 7.4 (5.8–11.8) | 8.9 (6.8–14.8) | 10.6 (7.6–18.8) | 10.5 (5.6–21.1) |
| COPD ex-smokers | 8.1 (5.3–10.3) | 7.7 (1.7–13.5) | 7.4 (2.6–13.9) | 9.9 (9.1–11.1) |
| Healthy smokers | 6.6 (5.7–8.8) | 6.5 (3.5–8.1) | 9.1 (9.1–11.5) | 9.9 (6.0–14.7) |
| Healthy nonsmokers | 6.7 (5.1–8.6) | 7.4 (4.5–10.3) | 9.4 (8.3–11.2) | 7.8 (6.7–8.3) |
Data are presented as geometric median (interquartile range).