Subgroup analyses (ATOS responders vs non-responders)—results. Data presented as median (IQR)
| Non-responder (n=24) | Responder (n=26) | P valuex) | Median effect (95% CI) responder—non-responder | |
| Baseline characteristics | ||||
| FEV1, % predicted | 29.4 (25.6, 36.9) | 30.1 (24.1, 33.4) | 0.67 | |
| RV,/TLC, % predicted | 182.8 (168.0, 203.0) | 199.3 (178.7, 209.6) | 0.18 | |
| FRC, % predicted | 207.7 (176.5, 240.3) | 228.7 (188.5, 252.7) | 0.42 | |
| PO2—rest with room air, mm Hg | 53.6 (52.0, 57.2) | 54.7 (50.4, 57.3) | 0.86 | |
| PCO2—rest with room air, mm Hg | 44.4 (39.5, 46.8) | 44.6 (38.1, 48.6) | 0.72 | |
| O2 flow rate—exercise, L/min | 3.5 (3.0, 4.0) | 3.0 (2.5, 4.0) | 0.42 | |
| Age, years | 66.5 (61.0, 73.0) | 62.0 (59.0, 68.0) | 0.20 | |
| BMI, kg/m2 | 24.3 (21.3, 26.4) | 23.7 (21.3, 26.1) | 0.45 | |
| Waist circumference, cm | 96.5 (89.5, 107.0) | 89.5 (83.0, 100.5) | 0.13 | |
| Waist–hip ratio | 0.97 (0.89, 1.0) | 0.91 (0.86, 0.98) | 0.14 | |
| ESWTATOS | ||||
| Mean O2-flow rate, L | 3.9 (2.6, 4.7) | 5.2 (3.9, 6.7) | 8.768E–03 | 1.6 (0.49 to 2.7) |
| Time, s | 280.0 (199.0, 857.0) | 751.5 (419.0, 1200.0) | 2.664E–03 | 268 (75 to 549) |
| Distance, m | 265.0 (155.0, 925.0) | 675.0 (350.0, 1210.0) | 1.287E–02 | 225 (50 to 530) |
| Blood gas analyses | ||||
| PO2rest, mm Hg | 65.4 (62.7, 67.9) | 65.1 (61.0, 68.6) | 0.75 | |
| PO2post, mm Hg | 66.3 (60.7, 73.2) | 74.1 (71.0, 76.6) | 3.364E–03 | 7.25 (2.4 to 11.6) |
| SaO2rest, mm Hg | 93.1 (91.4, 93.7) | 92.9 (91.7, 93.3) | 0.62 | |
| SaO2post, mm Hg | 91.8 (88.9, 93.7) | 93.5 (92.0, 94.2) | 4.141E–02 | 1.24 (0.04 to 2.8) |
| PCO2rest, mm Hg | 40.8 (39.9, 47.0) | 41.8 (39.0, 48.3) | 0.74 | |
| PCO2post, mm Hg | 48.3 (46.2, 53.6) | 51.6 (48.6, 56.1) | 0.23 | |
| Phrest | 7.41 (7.39, 7.43) | 7.41 (7.40, 7.43) | 0.68 | |
| Phpost | 7.36 (7.33, 7.38) | 7.34 (7.31, 7.36) | 0.05 | |
| Lactaterest, mmol/L | 1.2 (1.0, 1.6) | 1.0 (0.8, 1.2) | 0.14 | |
| Lactatepost, mmol/L | 1.9 (1.6, 2.4) | 1.4 (1.0, 2.2) | 0.08 | |
| Borg scale | ||||
| Dyspnoeapost, points | 6.0 (4.0, 7.5) | 5.0 (4.0, 5.0) | 1.107E–02 | –1 (–2 to 0) |
| ΔDyspnoea, points | 4.0 (3.0, 6.5) | 3.0 (2.0, 4.0) | 1.614E–03 | –1 (–2 to 0) |
| Leg fatiguepost, points | 6.0 (4.0, 7.5) | 4.0 (3.0, 5.0) | 0.35 | |
| ΔLeg fatigue, points | 4.0 (3.0, 6.5) | 2.0 (1.0, 3.0) | 0.58 |
Differences with p values<0.01 are presented in bold. Note: Median effects are not necessarily medians of differences; x) Mann-Whitney U test. P values are unadjusted for multiple comparisons.
ATOS, automatically titrating oxygen system; BMI, body mass index; ESWT, endurance shuttle walk test; FEV1, forced expiratory volume in 1 s; FRC, functional residual capacity; PCO2, partial pressure of carbon dioxide; pH, potential of hydrogen; PO2, partial pressure of oxygen; RV, residual volume; SaO2, oxygen saturation measured by blood gas analyses; TLC, total lung capacity.