The rate and predictors of continuous positive airway pressure adherence in Canadian patients with obstructive sleep apnea

Rationale: Obstructive sleep apnea (OSA) impacts mood, cardiovascular morbidity, and mortality. Continuous positive airway pressure (CPAP) is the first-line treatment for patients with moderate to severe OSA. CPAP ameliorates respiratory disturbances, leading to improvements in daytime sleepiness, quality of life, blood pressure, and cognition. However, despite its high efficacy, CPAP adherence is often sub-optimal. There are many factors that are proposed to affect CPAP adherence including: socio-demographic/economic characteristics, disease severity, psychological factors, side-effects, and initial experience with CPAP. Intervention studies have suggested that augmented support/education, cognitive behavioral therapy, and telemedicine may improve CPAP adherence. However, no studies regarding the rate and predictors of CPAP have been done within a Canadian context. Consequently, we sought to determine the rate and predictors correlated with CPAP adherence amongst Canadians. Methods: Patients referred for suspected OSA to the University of British Columbia Hospital Sleep Clinic between 2003 and 2009 were recruited. All patients underwent full polysomnography and completed a health questionnaire. Patient charts were reviewed, and CPAP adherence was defined as using the device for ≥4 hours for ≥70% of the time being used. CPAP predictors including severity of OSA, daytime sleepiness, age, BMI, depression, etc. were analysed. A P value of < 0.05 was considered to be statistically significant. Results: There were 1,250 patients in total; 844 were prescribed CPAP and 406 were not. Of those who were prescribed CPAP, 421 (49.9%) adhered to CPAP and 423 (50.1%) did not. In the multivariate model, the severity of OSA measured by AHI was the only predictor of CPAP adherence (p