CPAP adherence is associated with reduced risk for stroke among older adult Medicare beneficiaries with obstructive sleep apnea.

STUDY OBJECTIVES To examine the impact of adherence to continuous positive airway pressure (CPAP) therapy on risk for stroke among a nationally representative sample of older adults with obstructive sleep apnea (OSA). METHODS We performed a retrospective cohort study among Medicare beneficiaries aged ≥65 years who were newly diagnosed with OSA and initiated CPAP (2009-2013). Monthly indicators of CPAP adherence included charges for machines, masks, or supplies and were summed over 25-month follow-up to create a CPAP adherence variable. Stroke was modelled as a function of CPAP adherence using generalized estimating equations. RESULTS 5,757 beneficiaries met inclusion criteria and were included in the final sample. Of these, 407 (7%) experienced stroke. After adjusting for demographic and clinical characteristics, CPAP adherence was associated with reduced risk of stroke (hazard ratio 0.98; 95% confidence interval 0.96, 0.99) over 25 months, indicating a 2% reduction in risk of stroke for each month of CPAP adherence. When sensitivity analyses were performed to stratify results by time since first CPAP charge, the protective effect remained significant for the 12- and 6-month, but not 3-month, outcome models. CONCLUSIONS In this national analysis of older adult Medicare beneficiaries with OSA, CPAP adherence was associated with significantly reduced risk for stroke.