Untreated Sleep apnea doubles risk of high BP
A new study published in the journal Circulation has reported that untreated moderate or severe obstructive sleep apnea (OSA) was associated with increased odds of resistant hypertension contributing to inadequate BP control.
This uncontrolled high blood pressure can lead to strokes, heart attacks, and kidney disease, and African-Americans are more prone to such pathological abnormalities.
Dayna A. Johnson and associates conducted a study to investigate the association of sleep apnea with uncontrolled BP and resistant hypertension in blacks.
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Jackson Heart Sleep Study participants (N=913) underwent an in-home Type 3 sleep apnea study, clinic BP measurements, and anthropometry between 2012 and 2016.
Moderate or severe obstructive sleep apnea (OSA) was defined as a respiratory event index ≥15, and nocturnal hypoxemia was quantified as percent sleep time with <90% oxy-hemoglobin saturation. The study population has a mean age of 65 years.
Prevalent hypertension was defined as either a systolic BP ≥130 mm Hg or diastolic BP >80mm Hg, use of antihypertensive medication, or self-report of a diagnosis of hypertension.
Controlled BP was defined as systolic BP <130 mm Hg and diastolic BP <80 mm Hg; uncontrolled BP as systolic BP ≥130 mm Hg or diastolic BP ≥80 mm Hg with use of 1 to 2 classes of antihypertensive medication; and resistant BP as systolic BP ≥130 mm Hg or diastolic BP ≥80 mm Hg with the use of ≥3 classes of antihypertensive medication (including a diuretic) or use of ≥4 classes of antihypertensive medication regardless of BP level.
The key study findings of the analysis included are:
- Among the sample, 25.7% had OSA, which was untreated in 94% of participants. Overall,48% of participants had uncontrolled hypertension and 14% had resistant hypertension.
- After adjustment for confounders, participants with moderate or severe OSA had 2.0 times higher odds of resistant hypertension.
- Each standard deviation higher than <90% oxyhemoglobin saturation was associated with an adjusted odds ratio for resistant hypertension of 1.25.
- OSA and <90% oxyhemoglobin saturation was not associated with uncontrolled BP.
“But more research is needed to establish a cause-and-effect relationship between obstructive sleep apnea and resistant hypertension, said Dr. Robert M. Carey, a professor of medicine at the University of Virginia.
"It's a great study because it shows a potentially treatable association between obstructive sleep apnea and hypertension," said Carey, who was not part of the study. "This opens the door for more clinical trials to confirm the relationship."