| Demographics | Desaturators (n = 29) | Non-desaturators (n = 30) | p Value |
| Age (years) | 71 (9.1) | 70 (9.3) | 0.71 |
| Male (n (%)) | 14 (48%) | 19 (63%) | 0.24 |
| Smoking history (pack-years) | 36.4 (24.3) | 45.0 (27.9) | 0.17 |
| FEV1 (l) | 0.8 (0.5) | 0.9 (0.4) | 0.13 |
| FEV1 (% predicted) | 35.7 (15.1) | 38.7 (14.8) | 0.40 |
| FVC (l) | 1.7 (0.8) | 2.1 (0.8) | 0.04 |
| FVC (% predicted) | 57.8 (17.5) | 66.2 (17.1) | 0.04 |
| BMI (kg/m2) | 26.4 (5.4) | 25.6 (7.4) | 0.74 |
| Resting Pao2 (kPa) | 8.4 (1.2) | 9.4 (1.1) | 0.005 |
| Resting Paco2 (kPa) | 5.9 (0.9) | 5.2 (0.7) | 0.005 |
| Resting saturation (%) | 92.2 (2.2) | 93.5 (0.9) | 0.01 |
| MNS (night 1) (%)* | 90 (88, 91) | 93 (92, 94) | <0.0001 |
| MNS (night 2) (%)* | 89 (87, 90) | 93 (92, 94) | <0.0001 |
| TB90% (night 1)* | 67 (36, 88) | 3.9 (0.4, 8.2) | <0.0001 |
| TB90% (night 2)* | 74 (64, 94) | 2.0 (0.2, 6.0) | <0.0001 |
| Minimum nocturnal saturation (night 1)* (%) | 80 (72, 83) | 86 (81, 88) | <0.0001 |
| Minimum nocturnal saturation (night 2)* (%) | 78 (72, 83) | 84 (82, 88) | 0.0002 |
Data are presented as mean (SD) unless otherwise stated.
*Median (IQR).
BMI, body mass index; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; MNS, mean nocturnal saturation; Pao2, arterial oxygen tension; Paco2, arterial carbon dioxide tension; TB90%, time spent with saturation below 90%.