Nurose Karim, MD
Hypertension (HTN) is defined as systolic blood pressure (SBP) >140 mm Hg and diastolic blood pressure (DBP) >90 mm Hg in patients without prior stroke. It is one of the leading causes of primary and recurrent strokes. HTN is the third leading cause of death in women and fifth leading cause in men. As it is one of the modifiable risk factors for future strokes, in 2017, the American College of Cardiology (ACC)/American Heart Association (AHA) BP guideline set a lower BP target, SBP/DBP <130/80 mm Hg for patients with prior stroke. This study examines racial differences in BP control following a stroke using the 2017 ACC/AHA BP guideline thresholds and utilizing the data from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. This study reviewed participants taking antihypertensive medication who did (n=306) and did not (n=7,693) experience an adjudicated stroke between baseline (2003-2007) and a second study visit (2013-2016).
Among the 306 participants with a history of stroke, 50.3% of White participants and 39.3% of Black participants had controlled BP. Black participants were younger, more likely to be women with lower annual household income and less education, and were less likely to be married than White participants. Black participants with stroke were also current smoker, had BMI ≥30 kg/m2 and diabetes, and to be taking three or more classes of antihypertensive medication. For White participants with a history of stroke, having abdominal obesity was associated with a lower likelihood of BP control.
Among participants without a history of stroke, 56.0% of White participants and 50.2% of Black participants had controlled BP. Black participants with uncontrolled BP were younger, more likely to be women with an annual household income ≥$75,000 per year, were college graduate, married, and consume alcohol with BMI ≥30 kg/m2 and diabetes and to be taking ≥3 classes of antihypertensive medication than White participants.
Interestingly, the multivariable adjusted probability ratio for BP control comparing Black participants and White participants was 0.93, 95% CI: 0.76 – 1.15 for those with a history of stroke; the association was not statistically significant. And for those without a history of stroke, the association was marginally statistically significant, 0.97, 95% CI: 0.94 – 1.00, which is consistent with prior studies of the general population.
Although there has been a reduction in the overall stroke prevalence in the U.S. population in the past decade, racial disparities have sadly widened. This may be, in part, due to the difference in the incidence of HTN, per se, and difficulty in controlling BP in non-Hispanic Black adults.
The JNC 8 guideline recommends thiazide-type diuretic or calcium channel blocker as the first line antihypertensive medications in Black adults when there is no contraindication. This is based on randomized trials showing that Black adults have a smaller reduction in BP and risk for CVD events than White adults when treated with renin-angiotensin system blockers. Beta-blockers have also been shown to be associated with higher risks of CVD and CVD mortality compared with other antihypertensive medication. In the current study, a substantial proportion of Black participants were taking angiotensin converting enzyme inhibitor, angiotensin receptor blocker or beta blocker. We need to highlight guidelines recommended antihypertensive medication classes among Black adults with HTN.
As this study is using 2017 ACC/AHA BP guidelines, it does have some limitations. BP measurements in a single office visit are used to label patients as hypertensive or non-hypertensive. Also, the sample size of n=306 is modest. In a nutshell, combined effort at several levels is needed to overcome social disparities in health care and make it easily accessible.
