A new study shows a strong association between severe, untreated obstructive sleep apnoea and the risk of elevated blood pressure despite the use of high blood pressure medications.
The study involved patients who had cardiovascular risk factors or established heart disease and moderate or severe obstructive sleep apnoea. Among participants prescribed at least three antihypertensives including a diuretic, resistant elevated blood pressure was more prevalent in those with severe sleep apnoea (58.3 %) compared with moderate sleep apnoea (28.6%). Further analysis found that the odds of resistant elevated blood pressure were four times higher in participants with severe, untreated obstructive sleep apnoea even after adjusting for potential confounders such as body mass index, smoking status, diabetes mellitus, and cardiovascular disease (adjusted odds ratio = 4.12).
“Our findings suggest that severe obstructive sleep apnoea contributes to poor blood pressure control despite aggressive medication use,” says first author Harneet Walia, assistant professor at the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University. “This is an important finding from a clinical perspective as poor blood pressure control in patients taking multiple antihypertensive medications makes them particularly vulnerable to increased cardiovascular risk.”
Study results are published in the 15 August issue of the Journal of Clinical Sleep Medicine, which is published by the American Academy of Sleep Medicine.
“High blood pressure that is resistant to treatment with medications is a strong warning sign for the presence of obstructive sleep apnoea, a chronic disease that increases the risk for heart disease and stroke,” says American Academy of Sleep Medicine president Timothy Morgenthaler. “Over one-third of patients with hypertension and nearly eight out of 10 patients with treatment resistant hypertension have obstructive sleep apnoea. People who have high blood pressure should talk to a doctor about their risk for sleep apnoea.”
Data were analysed from the baseline examination of the Heart Biomarker Evaluation in Apnoea Treatment (HeartBEAT) study, a four-site randomised controlled trial comprising patients with moderate to severe obstructive sleep apnoea who were under cardiovascular disease management. The analysis involved 284 participants, of which 73 were prescribed an intensive antihypertensive regimen.
“Even under the close care of a cardiologist following national guidelines for treatment of cardiovascular risk and comprehensive medication regimens, severe levels of obstructive sleep apnoea versus a moderate level of obstructive sleep apnoea appear to be contributing to suboptimal blood pressure control,” says Walia.
The American Academy of Sleep Medicine reports that approximately 80% of people with drug-resistant high blood pressure have obstructive sleep apnoea, which involves repetitive episodes of complete or partial upper airway obstruction occurring during sleep despite an ongoing effort to breathe.
Research funding was provided by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH) and the National Center for Research Resources (NCRR).