Continuous Positive Airway Pressure Adherence for Prevention of Major Adverse Cerebrovascular and Cardiovascular Events in Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is associated with major adverse cerebrovascular and cardiovascular events (MACCEs) (1). Multiple studies have demonstrated the beneficial effects of continuous positive airway pressure (CPAP) therapy. When used optimally, CPAP can eliminate OSA-associated adverse effects, including hypoxemia, sleep fragmentation, swings in intrathoracic pressure, arousals, and sympathetic overactivity (1). Unexpectedly, the recent randomized controlled trials (RCTs) have failed to show that CPAP treatment reduces MACCEs (2–6). However, in these RCTs, the average daily use of CPAP was quite modest, and the conclusion that CPAP treatment was not associated with improved cardiovascular outcomes was based on intention-to-treat analyses, which included all CPAP-nonadherent participants. Yet, only adequate long-term adherence to CPAP could be associated with any improved outcome. Importantly, in the landmark SAVE (Sleep Apnea Cardiovascular Endpoints) trial, results from a propensity-score–matched (561 in each group) analysis, which does not preserve randomization, were significant in favor of CPAP users for stroke (P = 0.02) but not for cardiac events (6). It is therefore conceivable that composite endpoints consisting of both cerebrovascular and cardiac events could dilute the protective effect of CPAP on cerebrovascular outcomes in intention-to-treat populations.