Background: Blacks have a high prevalence of hypertension and uncontrolled blood pressure (BP), each of which may be partially explained by untreated sleep apnea. We investigated the association of sleep apnea with uncontrolled BP and resistant hypertension in blacks.
Methods: Between 2012 and 2016, Jackson Heart Sleep Study participants (N=913) underwent an in-home Type 3 sleep apnea study, clinic BP measurements, and anthropometry. 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% oxyhemoglobin saturation. 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. Multinomial logistic regression models were fit to determine the association between OSA severity and uncontrolled BP or resistant hypertension (versus controlled BP) after multivariable adjustment.
Results: The analytic sample with hypertension (N=664) had a mean age of 64.0 (SD,10.6) years, and were predominately female (69.1%), obese (58.6%), and college educated (51.3%). 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 a 2.0 times higher odds of resistant hypertension (95% confidence interval [CI], 1.14-3.67). Each standard deviation higher than <90% oxyhemoglobin saturation was associated with an adjusted odds ratio for resistant hypertension of 1.25 (95% CI 1.01-1.55). OSA and <90% oxyhemoglobin saturation were not associated with uncontrolled BP.
Conclusion: Untreated moderate or severe OSA is associated with increased odds of resistant hypertension. These results suggest that untreated OSA may contribute to inadequate BP control in blacks.
Keywords: blood pressure; hypertension; sleep apnea.