Table 2.
Comparing whether the criteria for introducing oxygen therapy are met or not.
| Meet the criteria for introducing oxygen therapy | ||||
|---|---|---|---|---|
| Yes | No | p-value | ||
| Patients | 88 (59.9) | 59 (40.1) | ||
| Patient characteristics at initiation of oxygenation therapy | ||||
| Age, year | 72.5 (67.0–78.8) | 71.0 (66.0–76.0) | 0.338 | |
| Sex, male | 72 (81.8) | 45 (76.3) | 0.414 | |
| Body mass index, kg/m2 | 22.2 (19.8–24.9) | 22.2 (19.6–25.0) | 0.828 | |
| Smoking history | 65 (73.9) | 47 (79.7) | 0.438 | |
| Duration of IPF, month | 46.5 (24.0–74.3) | 45 (26–66) | 0.539 | |
| Past history of acute exacerbation | 19 (21.6) | 9 (15.3) | 0.396 | |
| Surgical lung biopsy | 19 (21.6) | 45 (76.3) | 0.841 | |
| FVC, % predicted | 60.7 (49.9–72.3) | 62.0 (55.3–72.3) | 0.513 | |
| DLCO, %predicted | 38.9 (32.0–48.0) | 40.0 (29.5–52.2) | 0.902 | |
| Pulmonary hypertension | 53 (60.2) | 0 (0) | < 0.001 | |
| Resting hypoxaemia (SpO2 < 88%) | 22 (25.0) | 0 (0) | < 0.001 | |
| PaCO2 breathing air, mmHg | 40.6 (37.6–45.5) | 41.0 (37.7–45.0) | 0.652 | |
| 6MWT distance, m | 270 (171–385) | 298 (200–452) | 0.215 | |
| Minimum SpO2 on 6MWT, % | 80.0 (70.0–86.0) | 83.5 (73.0–88.0) | 0.068 | |
| CAT | 20.0 (15.0–26.0) | 21.0 (16.0–28.0) | 0.264 | |
| mMRC scale | 0.283 | |||
| 0 | 1 (1.1) | 2 (3.4) | ||
| 1 | 9 (10.2) | 9 (15.3) | ||
| 2 | 31 (53.2) | 22 (37.3) | ||
| 3 | 39 (44.3) | 17 (28.8) | ||
| 4 | 8 (9.1) | 9 (15.3) | ||
| GAP stage | 0.141 | |||
| I | 12 (13.6) | 11 (18.6) | ||
| II | 71 (80.7) | 48 (81.4) | ||
| III | 5 (5.7) | 0 (0) | ||
| Outcome | ||||
| Median survival time, days | 450 (259–641) | 662 (420–903) | 0.116 | |
| Death | 67 | 46 | 0.636 | |
| Chronic respiratory failure | 34 (50.7) | 25 (54.3) | ||
| Acute exacerbation | 19 (28.4) | 12 (26.1) | ||
| Lung cancer | 3 (4.4) | 2 (4.3) | ||
| Others | 11 (16.4) | 7 (15.2) | ||
| Lung transplantation | 1 | 0 | N/A | |
Data are presented as median (IQR) or n (%).
IQR, interquartile range; FVC, forced vital capacity; DLCO, diffusion capacity of the lung for carbon monoxide; SpO2, oxygen saturation of peripheral blood; PaCO2, arterial partial pressure of carbon dioxide; 6MWT, six-minute walk test; CAT, COPD assessment test; mMRC scale, modified Medical Research Council Dyspnea scale; GAP, gender age and physiology; N/A, not applicable.