Lower systolic BP target may reduce stroke risk

Issue: March 2015

NASHVILLE, Tenn. — In adults aged at least 60 years without diabetes or chronic kidney disease, risk for stroke was 70% higher for those with systolic BP in the 140-mm Hg to 149-mm Hg range compared with those with levels less than 140 mm Hg, according to new data from the Northern Manhattan Study.

Perspective from José Biller, MD

This finding conflicts with recommendations made by the panel convened for the Eighth Joint National Committee, whose report recommended treating systolic BP to less than 150 mm Hg in that patient population.

Ralph L. Sacco

“JNC 8 has caused, in my mind, some confusion,” Ralph L. Sacco, MD, MS, FAHA, FAAN, past president of the American Heart Association and researcher for the study, said during a press briefing at the International Stroke Conference. “[The JNC 8] basically moved the systolic BP level for those over age 60 with no chronic kidney disease (CKD) or diabetes. We all recognize that hypertension is a big contributor to stroke, and may be a contributor to some of the racial and ethnic disparities that are seen in stroke. Population-based data regarding the relationship between hypertension and stroke as an outcome are sparse, particularly in Hispanics and non-Hispanic blacks.”

Chuanhui Dong, PhD, research associate professor at University of Miami Miller School of Medicine, Sacco and colleagues analyzed 1,706 adults aged 60 years and older (mean age, 72 years). The cohort was 37% men and 49% Hispanic. All participants were free of stroke, diabetes and CKD at baseline.

The primary outcome was stroke.

At baseline, 43% of participants had systolic BP less than 140 mm Hg, 20% had systolic BP 140 mm Hg to 149 mm Hg and 37% had systolic BP of at least 150 mm Hg.

During a mean follow-up of 13 years, 167 strokes occurred. According to results presented, the crude rate of stroke was:

6.2 per 1,000 person-years for participants with systolic BP less than 140 mm Hg at baseline;
12.2 per 1,000 person-years for participants with systolic BP 140 mm Hg to 149 mm Hg at baseline; and
10 per 1,000 person-years for participants with systolic BP of at least 150 mm Hg at baseline.

The higher crude rate of stroke in the 140-mm Hg to 149-mm Hg group compared with the 150-mm Hg or more group may have been related to more people in the 150-mm Hg or more group taking medication, Sacco said at the press conference. He noted that there was not much difference in outcomes between those two systolic BP groups.

Compared with systolic BP less than 140 mm Hg at baseline, participants with 140 mm Hg to 149 mm Hg at baseline had an elevated risk for stroke (HR = 1.7; 95% CI, 1.2-2.6) after adjustment for age, sex, race/ethnicity and medication use. When the researchers analyzed only those not taking BP medication at baseline (n = 1,009), they found that participants with systolic BP 140 mm Hg to 149 mm Hg at baseline remained at elevated risk for stroke (HR = 1.7; 95% CI, 1-3).

Among those with systolic BP 140 mm Hg to 149 mm Hg at baseline, the increased risk for stroke was more pronounced in women (HR = 2) compared with men (HR = 1.3), and was significant in Hispanics (HR = 2.4; 95% CI, 1.3-4.7) and non-Hispanic blacks (HR = 2; 95% CI, 1-4.2) but not in non-Hispanic whites (HR = 0.8; 95% CI, 0.3-1.8), according to the researchers. There were not enough non-Hispanic whites in the study to draw definitive conclusions about their risk, Sacco said.

“Raising the threshold and changing the BP level to 150 mm Hg in this population could be deleterious and have a detrimental impact on the number of strokes we see,” said Sacco, chairman of the department of neurology, Olemberg family chair in neurological disorders; Miller professor of neurology, public health sciences, human genetics and neurosurgery; executive director of the Evelyn F. McKnight Brain Institute and chief of neurology service at Jackson Memorial Hospital, University of Miami Miller School of Medicine. “Other studies, both population-based studies and randomized trials, need to be done.” – by Erik Swain

Reference:

Dong C, et al. Abstract 79. Presented at: International Stroke Conference; Feb. 11-13, 2015; Nashville, Tenn.

Disclosure: Dong and Sacco report no relevant financial disclosures.

Perspective

José Biller, MD

There is always a concern about the J-curve when it comes to the brain. However, I think the observations and results of this study are telltale ingredients to support a recommendation of systolic BP less than 140 mm Hg in the studied patient population.

José Biller, MD

Professor and Chair of Neurology

Loyola University Chicago Stritch School of Medicine

Disclosures: Biller reports no relevant financial disclosures.