The evidence linking obstructive sleep apnea to cardiovascular disease continues to grow. Obstructive sleep apnea (OSA) is a thought to be a risk factor for the development of hypertension, stroke, coronary artery disease, and congestive heart failure. The evidence is strongest for hypertension. A recent study adds to the evidence linking OSA to stroke:
But the real question, Dr. Mohsenin said, is whether there is an independent association between sleep apnea and stroke, and a recent study on which he was an author shows that there is indeed such an association.
In the observational cohort study of 697 patients with obstructive sleep apnea and 325 controls (mean apnea-hypopnea index of 35 vs. 2 in the patients and controls, respectively), obstructive sleep apnea was found to have a statistically significant association with stroke or death (hazard ratio of 1.91) after adjustment for numerous factors, including age, sex, race, smoking status, alcohol consumption, body mass index, diabetes, hyperlipidemia, atrial fibrillation, and hypertension.
A trend analysis also showed a significant dose-response relationship between sleep apnea severity at baseline and development of a composite end point of stroke or death from any cause (N. Engl. J. Med. 2005;353:2034–41).
While randomized controlled trials are needed to firmly establish a causal link between sleep apnea and stroke—to “put the last nail in the coffin and say, ‘ok, sleep apnea is indeed a cause of stroke in a high-risk patient population,’” as Dr. Mohsenin put it, the findings increasingly suggest this is the case. Also, sleep apnea occurs as commonly in transient ischemic attack as it does in stroke, further underscoring the need for sleep apnea treatment in affected patients, he noted.
Additionally, a number of studies have shown that sleep apnea is associated with worse functional outcomes in stroke patients, Dr. Mohsenin said.
Patients with stroke who have sleep apnea have been shown to have more delirium, depression, impaired functional capacity, longer rehabilitation time, and longer hospitalization, he said.
“Sleep apnea does affect the outcome of stroke,” he said, noting that in some studies these effects lasted out to 12 months.
Patients who have had a stroke should be evaluated for sleep disordered breathing, he advised.
In the observational cohort study of 697 patients with obstructive sleep apnea and 325 controls (mean apnea-hypopnea index of 35 vs. 2 in the patients and controls, respectively), obstructive sleep apnea was found to have a statistically significant association with stroke or death (hazard ratio of 1.91) after adjustment for numerous factors, including age, sex, race, smoking status, alcohol consumption, body mass index, diabetes, hyperlipidemia, atrial fibrillation, and hypertension.
A trend analysis also showed a significant dose-response relationship between sleep apnea severity at baseline and development of a composite end point of stroke or death from any cause (N. Engl. J. Med. 2005;353:2034–41).
While randomized controlled trials are needed to firmly establish a causal link between sleep apnea and stroke—to “put the last nail in the coffin and say, ‘ok, sleep apnea is indeed a cause of stroke in a high-risk patient population,’” as Dr. Mohsenin put it, the findings increasingly suggest this is the case. Also, sleep apnea occurs as commonly in transient ischemic attack as it does in stroke, further underscoring the need for sleep apnea treatment in affected patients, he noted.
Additionally, a number of studies have shown that sleep apnea is associated with worse functional outcomes in stroke patients, Dr. Mohsenin said.
Patients with stroke who have sleep apnea have been shown to have more delirium, depression, impaired functional capacity, longer rehabilitation time, and longer hospitalization, he said.
“Sleep apnea does affect the outcome of stroke,” he said, noting that in some studies these effects lasted out to 12 months.
Patients who have had a stroke should be evaluated for sleep disordered breathing, he advised.
That the treatment of OSA improves cardiovascular outcomes is an unproven assumption. We know that in sleep apnea patients, CPAP can improve cardiac functioning (ejection fraction) and reduce blood pressure. However, it has not been proven that CPAP improves mortality or decreases the rate of myocardial infarction. A randomized controlled trial looking at this question would be difficult to carry out.
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