CPAP didn't reduce cardiac events in patients with obstructive sleep apnea and pre-existing CVD
Prescribing continuous positive airway pressure with the sole purpose of reducing future cardiovascular events in asymptomatic patients with obstructive sleep apnea and established cardiovascular disease cannot be recommended, an editorial stated.
Continuous positive airway pressure (CPAP) did not reduce cardiovascular events in patients with obstructive sleep apnea and coronary or cerebrovascular disease, a study found.
The international trial included 2,717 patients, between 45 and 75 years of age, with moderate to severe obstructive sleep apnea as determined by polysomnography and coronary or cerebrovascular disease. After a 1-week run-in of sham CPAP, they were randomized to CPAP plus usual care or usual care alone. The primary composite end point was death from cardiovascular causes, myocardial infarction, stroke, or hospitalization for unstable angina, heart failure, or transient ischemic attack. Secondary end points included the outcomes individually, other composites of them, revascularization, new-onset atrial fibrillation or diabetes, and death from any cause, as well as health-related quality of life, snoring symptoms, daytime sleepiness, and mood. The study was presented at the European Society of Cardiology meeting and was published by the New England Journal of Medicine on Aug. 28.
In patients receiving CPAP, the mean duration of use was 3.3 hours per night and the mean apnea-hypopnea index decreased from 29.0 events per hour at baseline to 3.7 events per hour during treatment. However, over a mean follow-up of 3.7 years, although slightly more patients in the CPAP group had at least 1 of the events in the primary end point (17% with CPAP vs. 15.4% with usual care; P=0.34), this difference was not statistically significant. The study also failed to find a significant effect on any other cardiovascular end point. The CPAP group did have significant improvements in snoring, daytime sleepiness, health-related quality of life, and mood compared to usual care patients.
Previous randomized trials have also failed to find reductions in cardiovascular events among patients assigned to CPAP, wrote the study authors. They noted that an ongoing challenge is patients' adherence to CPAP. The mean of 3.3 hours observed in this study is similar to other studies and clinical practice but may be insufficient to affect cardiovascular outcomes.
An accompanying editorial pointed out that when only the 561 patients who used CPAP for more than 4 hours a night were analyzed, there was a slight reduction in the primary endpoint (hazard ratio, 0.80; P=0.13) and a significant reduction in cerebrovascular events (hazard ratio, 0.52; P=0.02) compared to usual care patients, suggesting that how patients use CPAP is important. The editorialists recommended offering a CPAP trial to patients with obstructive sleep apnea who have symptoms or severe hypoxemia during sleep.
“However, on the basis of the results from [this] trial, prescribing CPAP with the sole purpose of reducing future cardiovascular events in asymptomatic patients with obstructive sleep apnea and established cardiovascular disease cannot be recommended,” the editorialists added.