The Apnea Positive Pressure Long-term Efficacy Study (APPLES): Rationale, design, methods, and procedures

Study Objective: To assess the size, time course, and durability of the effects of long-term continuous positive airway pressure (CPAP) therapy on neurocognitive function, mood, sleepiness, and quality of life in patients with obstructive sleep apnea. Design: Randomized, double-blinded, 2-arm, sham-controlled, multicenter, long-term, intention-to-treat trial of CPAP therapy. Setting: Sleep clinics and laboratories at 5 university medical centers and community-based hospitals. Patients or Participants: Target enrollment is 1100 randomly assigned subjects across 5 clinical centers. Interventions: Active versus sham (subtherapeutic) CPAP. Measurements and Results: A battery of conventional and novel tests designed to evaluate neurocognitive function, mood, sleepiness, and quality of life. Conclusions: The Apnea Positive Pressure Long-term Efficacy Study (APPLES) is designed to study obstructive sleep apnea and test the effects of CPAP through a comprehensive, controlled, and long-term trial in a large sample of subjects with obstructive sleep apnea.