Boston, MA - Continuous positive airway pressure (CPAP), the most widely prescribed therapy for treatment of obstructive sleep apnea, resulted in significantly lower blood pressure compared to either nocturnal supplemental oxygen or an educational control treatment, according to a new study from Brigham and Women's Hospital (BWH).
The study is published in the June 12, 2014 issue of The New England Journal of Medicine.
"The effect of CPAP on blood pressure in this study is important for both physicians and their patients," said Daniel Gottlieb, MD, MPH, lead study author and a physician-scientist in BWH's Division of Sleep and Circadian Disorders. "Previous studies have demonstrated that a decrease in blood pressure of this magnitude is associated with up to a 20 percent reduction in mortality from stroke and a 15 percent reduction in cardiovascular mortality."
Researchers in the Heart Biomarker Evaluation in Apnea Treatment (HeartBEAT) study, a randomized, single-blind clinical trial conducted at four medical centers with funding from the American Recovery and Reinvestment Act, screened patients with established coronary heart disease or multiple coronary heart disease risk factors for the presence of obstructive sleep apnea using questionnaire and home sleep testing.
A total of 318 patients, aged 45 to 75 years, with at least moderately severe obstructive sleep apnea (apnea-hypopnea index greater than or equal to 15 events per hour) were randomized to receive healthy lifestyle and sleep hygiene education alone (the control group), or in addition to either CPAP or nocturnal supplemental oxygen.
Researchers measured the participants' blood pressure over a 24-hour period before and after 12 weeks of treatment.
Researchers found that CPAP performed significantly better than either control or supplemental oxygen on lowering blood pressure. The effect of CPAP on blood pressure was greatest at night, the time when sleep apnea often prevents the expected fall in blood pressure, and was greater for diastolic than for systolic blood pressure. Moreover, the decrease in blood pressure was seen despite generally well-controlled blood pressure at baseline.
"Studies like HeartBEAT provide an opportunity to rigorously test apnea treatment options, which should help physicians determine best treatments for individual patients," said James Kiley, PhD, director, Division of Lung Disease, National Heart, Lung, and Blood Institute, part of the National Institutes of Health.
Obstructive sleep apnea is characterized by repeated breathing pauses during sleep due to collapse of the upper airway. It is a common chronic condition, affecting an estimated nine percent of middle-aged women and 24 percent of middle-aged men, and is an established risk factor of hypertension. Treatment of sleep apnea with CPAP has been shown to reduce blood pressure in patients with previously untreated hypertension and in those with treatment-resistant hypertension.
Other participating institutions in the study were Case Western Reserve University, Johns Hopkins University, and the VA Boston Healthcare System.
This research was supported by the National Heart, Lung, and Blood Institute (RC2 HL101417, 1R01HL109493, R21HL108226) and by a grant from the National Center for Research Resources.
Brigham and Women's Hospital (BWH) is a 793-bed nonprofit teaching affiliate of Harvard Medical School and a founding member of Partners HealthCare. BWH has more than 3.5 million annual patient visits, is the largest birthing center in Massachusetts and employs nearly 15,000 people. The Brigham's medical preeminence dates back to 1832, and today that rich history in clinical care is coupled with its national leadership in patient care, quality improvement and patient safety initiatives, and its dedication to research, innovation, community engagement and educating and training the next generation of health care professionals. Through investigation and discovery conducted at its Brigham Research Institute (BRI), BWH is an international leader in basic, clinical and translational research on human diseases, more than 1,000 physician-investigators and renowned biomedical scientists and faculty supported by nearly $650 million in funding. For the last 25 years, BWH ranked second in research funding from the National Institutes of Health (NIH) among independent hospitals. BWH continually pushes the boundaries of medicine, including building on its legacy in transplantation by performing a partial face transplant in 2009 and the nation's first full face transplant in 2011. BWH is also home to major landmark epidemiologic population studies, including the Nurses' and Physicians' Health Studies and the Women's Health Initiative. For more information, resources and to follow us on social media, please visit BWH's online newsroom.