Table 1.
Subject Characteristics of the Derivation and Validation Datasets
| Characteristic | Derivation Dataset (n = 307) | Validation Dataset (n = 308) | P value |
|---|---|---|---|
| Age, mean (SD) | 49.9 (14.4) | 43.8 (8.3) | < 0.001 |
| Men, % | 66.1 | 99.0 | < 0.001 |
| Body mass index (kg/m2), mean (SD) | 25.5 (4.2) | 23.7 (3.3) | < 0.001 |
| Smoking history | < 0.001‡ | ||
| Present smoker, % | 31.4 | 55.4 | |
| Never smoker, % | 43.1 | 19.7 | |
| Snoring, % | 80.5 | 48.9 | < 0.001 |
| Excessive daytime sleepiness | |||
| Epworth Sleepiness Scale, mean (SD) | 7.1 (4.3) | 6.6 (3.7) | 0.165 |
| Hypertension , % | 48.9 | 16.1 | < 0.001 |
| Systolic blood pressure (mm Hg), mean (SD) | 128.2 (19.3) | 129.0 (14.3) | 0.562 |
| Diastolic blood pressure (mm Hg), mean (SD) | 82.5 (12.5) | 80.9 (10.8) | 0.081 |
| Diabetes, % | 4.6 | 9.3 | 0.037 |
| Cerebrovascular disease, % | 3.6 | 1.8 | 0.127 |
| Cardiovascular disease, % | 5.5 | 3.6 | 0.337 |
| Oxygen desaturation index*, mean (SD) | 22.1 (28.3) | 7.9 (10.1) | < 0.001 |
| Respiratory disturbance index†, mean (SD) | NA | 10.7 (11.6) | NA |
*
Oxygen desaturation index is defined as a fall of greater than 4% per hour in arterial oxygen saturation during sleep study.
†
Respiratory disturbance index is the number of apneas and hypopneas per hour of sleep study.
‡
P value for trend, χ2 test.