Table 1.
Anthropometric, Lung Volumes, Blood Gas, and Sleep Data of Patients Classified by the Presence of Daytime Hypoxemia (PaO2 %<90 of Predicted)
| PaO2%<90 (n = 372) | PaO2%>90 (n = 84) | P-value (#) | |
|---|---|---|---|
| Mean ± SD | Mean ± SD | ||
| Sex (% (n) male) | 63.7 (237) | 70.2 (52) | 0.311 |
| Age (yr) | 48.1 ± 11.9 | 55.2 ± 12.1 | <0.001 |
| BMI (Kg/m2) | 44.3 ± 10.5 | 35.8 ± 12.1 | <0.001 |
| BSA (m2) | 2.36 ± 0.32 | 2.09 ± 0.26 | <0.001 |
| VC (% pred.) | 92.9 ± 14.5 | 99.2 ± 16.1 | 0.0013 |
| FEV1 (% of pred.) | 91.3 ± 17.1 | 110.3 ± 18.1 | <0.001 |
| FEV1/VC (abs value) | 78.3 ± 8.4 | 79.4 ± 7.7 | 0.2531 |
| FRC (% of pred.) | 75.5 ± 20.5 | 83.3 ± 20.6 | 0.0017 |
| RV (% of pred.) | 90.4 ± 23.9 | 90.1 ± 17.7 | 0.9162 |
| TLC (% of pred.) | 90.7 ± 12.3 | 94.0 ± 13.4 | 0.0302 |
| MEF50 (% of pred.) | 90.9 ± 34.5 | 96.2 ± 36.3 | 0.2083 |
| PaO2 (mmHg) | 68.9 ± 7.7 | 83.9 ± 6.4 | <0.001 |
| PaCO2 (mmHg) | 40.4 ± 4.7 | 37.0 ± 3.1 | <0.001 |
| AHI (event-hour-1) | 50.7 ± 34.2 | 38.2 ± 25.7 | 0.0021 |
| ODI (event-hour-1) | 52.1 ± 34.2 | 37.6 ± 25.3 | <0.001 |
| TST90 (%) | 13.1 ± 42.7 § | 1.45 ± 15.6 § | <0.001 |
BMI= body mass index; BSA = body surface area; RV = residual volume; MEF50: expiratory flow at 50% of FVC. AHI = apnea and hypopnea index; ODI = oxygen desaturation index; TST90 = total sleep time spent with SaO2 <90% (% of total sleep time).
#
P-values were computed by t-tests of two independent populations with equal or unequal variances, Fisher's exact χ2 test for sex, and Mann-Whitney U test for TST90.
§
Median ± Interquartile Range