Patient characteristics
| Subtherapeutic CPAP | Therapeutic CPAP | p-value | |
| Patients n | 51 | 51 | |
| Age yrs | 48.7±10.6 | 48.1±9.5 | 0.77 |
| Weight kg | 111.3±22.0 | 115.5±25.1 | 0.37 |
| BMI kg·m−2 | 34.5±5.0 | 35.8±7.3 | 0.30 |
| Neck circumference cm | 44.6±3.3 | 45.1±4.0 | 0.54 |
| Waist/hip circumference ratio | 1.01±0.06 | 1.02±0.06 | 0.93 |
| Current smokers % | 17.7 | 21.6 | 0.62 |
| Ex-smokers % | 54.9 | 43.2 | 0.24 |
| Hypertensive % | 25.5 | 21.6 | 0.64 |
| Patients on antihypertensive therapy % | 25.5 | 21.6 | 0.64 |
| Diabetics % | 2.0 | 2.0 | 1.00 |
| Patients with coronary artery disease % | 0.0 | 7.4 | 0.04 |
| Oxygen saturation dips >4% per hour of sleep | 42.7±21.6 | 41.9±25.4 | 0.87 |
| ESS at baseline | 15.2±4.0 | 15.8±4.0 | 0.48 |
| Osler test at baseline min | 17.3±13.1 | 18.1±13.1 | 0.75 |
| CPAP compliance at study end h·night−1 | 3.9±2.5 | 4.7±2.1 | 0.08 |
| Retitration CPAP pressure following study cmH2O | 10.1±1.6 | 10.0±1.9 | 0.72 |
Data are presented as mean±sd, unless otherwise stated. CPAP: continuous positive airway pressure; BMI: body mass index; ESS: Epworth Sleepiness Score; Osler: Oxford sleep resistance.