Table A11: Summary of Key Study Characteristics*.
| Study | Baseline FEV1 % Predicted (L) (Mean)† | Baseline PaO2 (mm Hg)(Mean)‡ | Baseline PaCO2 (mm Hg) (Mean)§ | Follow-up | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Total║ | LTOT | Control | Total║ | LTOT | Control | Total║ | LTOT | Control | Mean (SD) or Range (Years) | |
| Severe Hypoxemia | ||||||||||
| MRC (10) | 0.66 | 0.67 | 0.64 | 50.8 | 49.9 | 51.7 | 54.4 | 54.9 | 53.9 | 0−5 |
| Mild-to-moderate Hypoxemia | ||||||||||
| Gorecka et al (24) | 29.8 | 29.7 | 29.8 | 60.4 | 59.5 | 61.3 | 44.1 | 45.3 | 42.8 | 0.2−7 |
| Haidl et al (25) | 40.8 | 38.8 | 42.7 | 66.5 | 65.6 | 67.3 | 40.8 | 41.9 | 39.7 | 1−3 |
| Garcia-Aymerich et al (35), ¶ | 36 | - | - | 64 | ? | - | - | - | - | 1.1 (0.5) |
| Kessler et al (36), ¶ | 39 | - | - | 66 | <60 | - | 46 | - | - | 0−1 |
Abbreviations: FEV1, forced expiratory volume in 1 second; LTOT, long-term oxygen therapy treatment group; mm Hg, millimetres of mercury; O2, oxygen; PaO2, arterial partial pressure of oxygen; PaCO2, arterial partial pressure of carbon dioxide, SD, standard deviation.
COPD Stage: mild, FEV1 > 80% predicted; moderate, FEV1 > 50% and < 80% predicted; severe, FEV1 > 30% and < 50% predicted; very severe, FEV1 < 30%. Severe COPD defined as FEV1 < 1.5 litres.
Hypoxemia: severe, < 50 mm Hg; mild-to-moderate, ~ 50-65 mm Hg.
Hypercapnia: > 45-60 mm Hg.
Total: study population as a whole including treatment and control groups, either taken from the original paper or calculated as the mean from the 2 arms of the trial.
Heterogeneity in the comparison: COPD patients using O2 have severe hypoxemia and COPD patients not using O2 (e.g., controls) have mild-to-moderate hypoxemia.