Evaluation of continuous positive airway pressure adherence and its contributing factors.

Background: Continuous positive airway pressure (CPAP) adherence may vary based on the study design and country.

Objectives: To investigate long-term CPAP adherence and elucidate associated factors.

Methods: A multicenter retrospective observational cohort study was conducted over two years. The study included patients diagnosed with obstructive sleep apnea who were prescribed CPAP (n = 1261). Adherence was assessed for 90 days and 365 days. Centers for Medicare and Medicaid Services (CMS) criteria (≥4 h/night on ≥70 % of nights) and research adherence criteria (≥4 h/night during the observational period) were used. Factors influencing CPAP adherence (CMS criteria) during 90 and 365 days were also evaluated. Continuous variables were categorized into low, middle, and high classes, and logistic regression analysis with interaction was performed.

Results: CPAP adherence to CMS criteria for 90 and 365 days was 45.6 % and 44.7 %, respectively, whereas adherence to research criteria was 57.0 % and 54.1 %, respectively. Middle age, high age, and high apnea ratio independently increased CPAP adherence. Conversely, a high rapid eye movement apnea-hypopnea index ratio decreased CPAP adherence. Although high body mass index (BMI) had no independent effect on adherence, its interaction with high 3 % oxygen desaturation index increased 90-day CPAP adherence. However, high BMI decreased 90-day CPAP adherence in males. The interaction between middle age and high BMI was associated with decreased CPAP adherence over 365 days.

Conclusions: Adherence to CPAP in real-world settings is modest. Various factors influence CPAP adherence. BMI may exert varied effects on CPAP adherence depending on the accompanying factors.