Table 2.
6MWT of patients with stable end-stage lung diseases without and with wearing a mask
| Without mask | With mask | Mean difference (95% CI) | Test for equivalence p value | |
|---|---|---|---|---|
| Oxygen supply during 6MWT, L/min mean (SD) | 1.95 (1.6) | 2.01 (1.5) | 0.06 (–0.15 to 0.27) | <0.001 |
| 6MWD, m mean (SD) | ||||
| All (n = 31) | 306.9 (101.9) | 305.7 (103.8) | –1.19 (–13.4 to 11.0) | <0.001 |
| COPD (n = 20) | 279.0 (103.6) | 271.6 (106.5) | –7.45 (–24.2 to 9.3) | 0.0145 |
| ILD (n = 7) | 339.4 (92.8) | 356.9 (79.9) | 17.43 (–7.8 to 42.7) | – |
| Others (n = 4) | 389.5 (44.2) | 387.0 (23.8) | –2.50 (–36.6 to 31.6) | – |
| Oxygen saturation at maximum exercise, % mean (SD) | ||||
| All (n = 31) | 88.3 (8.0) | 89.0 (7.1) | 0.06 (–1.4 to 2.8) | 0.003 |
| COPD (n = 20) | 89.6 (6.2) | 90.0 (7.0) | 0.40 (–1.3 to 2.1) | 0.003 |
| ILD (n = 7) | 83.3 (44.2) | 84.3 (23.8) | 1.00 (–8.4 to 10.4) | – |
| Others (n = 4) | 91.0 (7.3) | 92.5 (4.0) | 1.50 (–5.9 to 8.9) | – |
The t tests were not performed due to limited validity in the groups with small sample sizes. CI, confidence interval; COPD, chronic obstructive pulmonary disease; ILD, interstitial lung disease; SD, standard deviation; 6MWD, 6-minute walk distance; 6MWT, 6-minute walk test.