(RxWiki News) The link between obstructive sleep apnea and high blood pressure has been known among doctors for a while. But it may be a stronger link than most realize.
A recent study found that those with severe obstructive sleep apnea, when not treated, is linked to high blood pressure even when a person is taking blood pressure medications.
The most common treatment for obstructive sleep apnea is continuous positive airway pressure, or CPAP.
CPAP requires that a person wear a mask that pumps air into their airways during sleep.
"Treat obstructive sleep apnea."
The study, led by Hameet Walia, MD, of the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, looked at the link between obstructive sleep apnea and high blood pressure.
The researchers studied 284 participants who had untreated moderate to severe obstructive sleep apnea and who were at risk for heart disease or related conditions.
Among those with high blood pressure, the participants were classified in one of three groups:
- having blood pressure under control, with a blood pressure lower than 130/80
- having high blood pressure not under control, higher than 130/80 and not taking blood pressure medications
- having high blood pressure despite taking medications for it
Overall, 62 percent of the participants had controlled blood pressure, 28 percent had uncontrolled high blood pressure and 10 percent had high blood pressure despite taking medication.
Overall, 24 percent of those in the study had severe obstructive sleep apnea.
Then the researchers looked the which of the blood pressure categories the individuals were in based on how bad their sleep apnea was.
They found that having high blood pressure despite taking medications was more common among those with severe sleep apnea than among those with moderate sleep apnea.
While 58 percent of those with severe sleep apnea had uncontrolled blood pressure despite medication, only 29 percent of those with moderate sleep apnea had uncontrolled blood pressure.
After taking into account differences in age, sex, race, weight and history of heart disease, diabetes and smoking, those with severe obstructive sleep apnea had four times greater odds of having uncontrolled blood pressure than those with moderate sleep apnea.
"Among patients with increased cardiovascular risk and moderate to severe obstructive sleep apnea, untreated severe compared to moderate obstructive sleep apnea was associated with elevated blood pressure" despite intensive drugs to control blood pressure, the researchers wrote.
They concluded that this finding suggested "untreated severe obstructive sleep apnea contributes to poor blood pressure control despite aggressive medication."
William Kohler, MD, the medical director of the Florida Sleep Institute in Spring Hill, Florida, said the link between high blood pressure and obstructive sleep apnea has long been established.
"All patients with hypertension should be screened for possible obstructive sleep apnea, particularly those that have uncontrolled high blood pressure," he said.
"Sleep apnea is a significant contributing factor to high blood pressure," Dr. Kohler said. "If it is the primary cause, treating the sleep apnea may allow the person to decrease or actually discontinue their antihypertensive medication."
The study was published August 15 in the Journal of Clinical Sleep Medicine. The research was funded by the National Heart Lung Blood Institute and the National Center for Research Resources.
One author has received research support from a dozen different pharmaceutical companies, and another has consulted for Saatchi and Saatchi. Five authors have received research support from Philips Respironics and/or Res Med, and one of these has also consulted for Apnex Medical, Apnicure and Vertex Pharmaceuticals.