DeVilbiss AutoAdjust With SmartFlex Comparative Study

Inclusion Criteria: * Epworth Sleepiness Scale \>10 * Body Mass Index \> 26 * Apnea-hypopnea index (AHI) ≥15 (mod to severe range) * AHI ≤ 10 at therapeutic continuous positive airway pressure (CPAP) pressure * CPAP naïve patients * Polysomnogram (PSG) within 3 months of enrollment * Average oxygen saturation by pulse oximetry (SpO2) \> 90% during titration * Sleep efficiency on titration night ≥ 78% Exclusion Criteria: * Diagnosis of mild obstructive sleep apnea (OSA) * Co-morbid conditions which render participation to be at risk these may include patients with congestive heart failure, chronic obstructive pulmonary disease (COPD) or psychiatric illness * Allergies to mask materials * Difficulties with nasal breathing * Evidence of another primary sleep disorder * Evidence of arousing periodic limb movements during titration * Contraindications as listed on product labeling. * Pregnant * Currently diagnosed with depression if symptomatic * Predominately central sleep apnea * Deemed medically unsuitable by investigator * Evidence of any type of infection or treatment of an infectious condition during the period of research participation * Full Face Mask during titration * Have a bi-level requirement * CPAP pressure \>15cmH2O * Subjects with tracheotomy * Uncontrolled hypertension * Require supplemental oxygen * Stimulants, major tranquillizers or antipsychotics.