Objectives: To examine if reported obstructive sleep apnea (OSA) symptom improvement, baseline depressive symptoms, or polysomnographically measured sleep parameters are associated with adherence to continuous positive airway pressure (CPAP). CPAP is a highly effective treatment for OSA. Low adherence to CPAP therapy is common and poorly understood. Depression and lack of perceived benefits from CPAP are possible reasons for low adherence.
Methods: Seventy-eight patients evaluated for OSA at a sleep medicine center agreed to participate in the study; 54 patients completed all study assessments. The Beck Depression Inventory (BDI) and the functional outcomes of sleep questionnaire (FOSQ) were administered before polysomnographic evaluation. A card embedded in the CPAP device electronically recorded adherence. The BDI and FOSQ were administered 1 to 2 months after the baseline measurements were obtained.
Results: Baseline depressive symptoms were not correlated with mean duration of CPAP use per night. Reported improvements in OSA symptoms were correlated positively with CPAP adherence. There were significant positive correlations between improvement in depressive symptoms and OSA symptoms after initiation of CPAP therapy. The polysomnographic variables measured did not predict improvement in daytime OSA symptoms or CPAP adherence. Post hoc analyses suggested that those individuals with baseline Apnea Hypopnea Index (AHI) between 40 and 80 experienced more symptom improvement than those with AHI <40 or >80.
Conclusions: Patients with the greatest level of CPAP adherence also reported the greatest improvement in OSA symptoms. Patients who continued to experience OSA symptoms after CPAP treatment also tended to have more depressive symptoms after CPAP treatment.