WEDNESDAY, Nov. 9 (HealthDay News) -- Sleep apnea is a significant risk factor for stroke or death from any cause, according to a study in the Nov. 10 issue of the New England Journal of Medicine. A second study in the same issue suggests that continuous positive airway pressure (CPAP) treatment does not improve survival of heart failure patients with sleep apnea.
T. Douglas Bradley, M.D., of the University of Toronto, and the Canadian Positive Airway Pressure (CANPAP) investigators randomly assigned 258 patients with heart failure and central sleep apnea caused by loss of respiratory drive to receive CPAP or no treatment. While the authors found that CPAP treatment reduced norepinephrine and increased ejection fraction and exercise tolerance, no mortality benefit was observed. In fact, early divergence of survival curves favored the control group.
In the second study, H. Klar Yaggi, M.D., of Yale University School of Medicine, and colleagues examined the role of obstructive sleep apnea, caused by loss of upper-airway tone, in the risk of stroke or death from any cause. The authors found sleep apnea to be a strong risk factor for stroke and death even after adjustment for other risk factors, inflicting a hazard ratio of 3.3 for the combined outcome in patients with severe apnea.
"A clear majority of studies are supportive of the notion that obstructive sleep apnea is a causal mechanism in cardiac and vascular disease," according to an editorial. "However, there are no large-scale, randomized trials of cardiovascular events or survival with continuous positive airway pressure treatment."
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