Is inconsistent pre-treatment bedtime related to CPAP non-adherence?

Lack of adherence to continuous positive airway pressure therapy (CPAP) limits the effectiveness of treatment of obstructive sleep apnea (OSA). We hypothesized that an irregular bedtime would be negatively related to regular use of CPAP treatment. If so, modifying bedtime schedule may address the persistent problem of inconsistent CPAP use in adults with OSA. In a prospective longitudinal study, we examined whether inconsistent self-reported bedtime before initiation of CPAP treatment, operationalized as bedtime variability, was (1) different among those adherent (≥4 hours per night) and non-adherent to CPAP treatment at 1 week and 1 month; and/or (2) was related to 1-week and 1-month CPAP use when other variables were accounted for. Consecutively recruited newly diagnosed OSA adults (n = 79) completed sleep diaries prior to CPAP treatment. One-week and 1-month objective CPAP use data were collected. Pre-treatment bedtime variability was different among CPAP non-adherers and adherers at 1 month and was a significant predictor of non-adherence at 1 month in multi-variable analyses. The odds of 1-month CPAP non-adherence were 3.5 times greater in those whose pre-treatment bedtimes varied by >75 minutes. Addressing sleep schedule prior to CPAP initiation may be an opportunity to improve CPAP adherence.