Is continuous positive airway pressure, when used in patients with mild to moderate obstructive sleep apnea, associated with a decreased risk of cardiovascular disease?

The use of continuous positive airway pressure (CPAP) in patients with mild to moderate obstructive sleep apnea (OSA) is associated with a decreased risk of fatal and nonfatal cardiovascular events. Since we also have data that CPAP decreases motor vehicle accidents, it is reasonable to recommend CPAP until we have randomized controlled trial data that shows its use to be harmful. (LOE = 2b)

Buchner NJ, Sanner BM, Borgel J, Rump LC. Continuous positive airway pressure treatment of mild to moderate obstructive sleep apnea reduces cardiovascular risk. Am J Respir Crit Care Med 2007;176(12):1274-80.  [PMID:17673692]

Cohort (prospective)

Unknown/not stated

Outpatient (specialty)

CPAP has been shown to improve daytime alertness and decrease motor vehicle accidents in patients with OSA. Additionally, patients with severe OSA treated with CPAP have a decrease in cardiovascular events. These researchers wanted to see if there might also be a cardiovascular benefit in patients with mild to moderate OSA. They recruited all patients who came to their sleep center over a 5-year period and enrolled a total of 288 patients with mild to moderate OSA. OSA was considered present when no air flow was measured for more than 10 seconds in the presence of paradoxical chest wall motion. Hypopnea was defined as a 50% reduction in airflow for more than 10 seconds. Mild OSA was defined as having 5 to 15 episodes of apnea or hypopnea per hour and moderate OSA was 15 to 30 episodes per hour. The physicians recommended CPAP in patients with moderate to severe OSA and to patients with mild OSA who also had severe daytime hypersomnolence. Patients could choose to use CPAP, oral appliances, or no treatment. The researchers evaluated the patients annually with a standardized set of surveys. When patients died during the follow-up period, the researchers checked death certificates and autopsy reports. The median follow up was 6 years. At the onset, the patients treated with CPAP had higher body mass index (31 vs 29 kg/m2). Otherwise, the groups were similar on other cardiovascular risk factors. Twenty of the 78 patients (25.3%) with mild to moderate OSA who were not treated had fatal or nonfatal cardiovascular events compared with 30 of the 209 who chose to use CPAP (14.4%; P = .024). After adjusting for other cardiovascular risk factors, CPAP use contributed approximately one third of the risk of developing a cardiovascular event. Although these findings are consistent with what has been seen in severe OSA, this is not a randomized trial, so the results could be explained by other factors that could not be accounted for.