CPAP Most Effective for Treating Sleep Apnea

Continuous positive airway pressure (CPAP) is better than giving oxygen at night to tackle the cardiovascular risks of obstructive sleep apnea (OSA), according to a new study.

Researchers at Brigham and Women's Hospital (BWH; Boston, MA, USA) conducted a randomized, controlled trial involving 318 patients with cardiovascular disease (CVD) or multiple cardiovascular risk factors. The patients were screened for OSA with the use of the Berlin questionnaire, and home sleep testing was used to establish the diagnosis. Participants with an apnea-hypopnea index of 15-50 events per hour were randomly assigned to receive education on sleep hygiene and healthy lifestyle alone (controls) or, in addition to education, either CPAP or nocturnal supplemental oxygen. The primary outcome was 24-hour mean arterial pressure.

The results showed that on average, the 24-hour mean arterial pressure at 12 weeks was lower in the group receiving CPAP than in the control group, or in the group receiving supplemental oxygen. There was no significant difference in 24-hour mean arterial pressure between the control group and the group receiving oxygen. A sensitivity analysis performed with the use of multiple imputation approaches to assess the effect of missing data did not change the results of the primary analysis. The study was published on June 12, 2014, in the New England Journal of Medicine (NEJM).

“CPAP cut 24-hour mean arterial blood pressure by 2.8 mmHg more than did supplemental oxygen at night,” concluded lead author Daniel Gottlieb, MD, MPH, of BWH, and colleagues. “Previous studies have demonstrated that a decrease in blood pressure of this magnitude is associated with up to a 20% reduction in mortality from stroke and a 15% reduction in cardiovascular mortality.”

In OSA, the muscles in the throat close in and block the airway during sleep. These gaps in breathing cause blood pressure to go up, because the oxygen level in the body falls and the brain sends signals to the blood vessels to contract so that oxygen flow to the heart and brain is increased. CPAP is the most commonly prescribed treatment for OSA, involving a mask worn during sleep that pumps air to help prevent the airway from closing.

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Brigham and Women's Hospital
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