Study casts doubt on impact of CPAP therapy on cardiovascular events
WALTHAM, Mass. – CPAP therapy plus usual care, versus usual care alone, does not prevent cardiovascular events in patients with moderate-to-severe obstructive sleep apnea and established cardiovascular disease, according to a study published Aug. 28 on the website of the New England Journal of Medicine.
“This study was not powered to provide definitive answers regarding the effects of CPAP on secondary cardiovascular end points, but there was no indication of a significant benefit with respect to any cause-specific cardiovascular outcome,” the study states.
The Sleep Apnea Cardiovascular Endpoints (SAVE) study found that CPAP therapy significantly reduced snoring and daytime sleepiness, and improved health-related quality of life and mood, but it had “no significant effect” on so-called “primary composite end points.” These end points include death from cardiovascular causes, myocardial infarction, stroke, or hospitalization for unstable angina, heart failure or transient ischemic attack.
As part of the study, researchers randomly assigned 2,717 eligible adults between 45 and 75 years of age who had moderate-to-severe sleep apnea and coronary or cerebrovascular disease to receive CPAP therapy plus usual care, or usual care alone. After a mean follow-up of 3.7 years, they found an end-point event had occurred in 229 patients in the CPAP group vs. 207 in the usual care group.
The study, funded by the National Health and Medical Research Council of Australia and others, sought to determine whether or not CPAP therapy could be a useful additional treatment for the prevention of these events.
“Observational clinical studies have shown that the use of CPAP is associated with lower rates of cardiovascular complications and of death from cardiovascular causes, especially among patients who are adherent to treatment,” the report states. “Obstructive sleep apnea is a common condition among patients with cardiovascular disease, affecting 40% to 60% of such patients.”