The Rate and Predictors of Continuous Positive Airway Pressure Adherence in Patients with Obstructive Sleep Apnea Presenting to a Sleep Clinic in British Columbia

Abstract

Purpose: Obstructive sleep apnea (OSA) is characterized by repetitive episodes of upper airway obstruction while asleep that leads to sleep fragmentation and hypoxemia. OSA is associated with an increased rate of cardiovascular disease, motor vehicle crashes, stroke, and all-cause mortality. Continuous positive airway pressure (CPAP) improves upper airway collapse, and its use is associated with improved daytime sleepiness and reduced rates of cardiovascular disease and motor vehicle crashes. However, one of the major challenges associated with the success of CPAP is adherence. To date, there have been no studies on the rate or predictors of CPAP adherence in Canadians. We sought to determine the rate and predictors of CPAP adherence amongst a sample of patients presenting to the University of British Columbia Sleep Disorders Clinic (UBC SDC). Methods: Patients referred for suspected OSA to the UBC SDC were recruited and underwent attended overnight polysomnography and completed a health questionnaire. Patient charts were reviewed, and CPAP adherence was defined according to the recognized standard of CPAP use for  4 hours per night for 70% of nights. Results: In total, 1,250 patients were recruited. Of these, 844 were prescribed CPAP and 421 (49.9%) were adherent. The severity of OSA was the only significant predictor of CPAP adherence (p < 0.01). Adherent patients had a mean apnea hypopnea index (AHI) of 34 events/hr compared to 27 events/hr in non-adherent patients. Conclusion: CPAP adherence was relatively low (49.9%) and OSA severity was its only significant predictor in our cohort.