Reductions in Stroke Observed With BP Less Than 140 mm Hg, Fueling Support for Lower Threshold
A new analysis is challenging the current blood-pressure treatment thresholds from the 8th Joint National Committee (JNC8) by finding evidence of harm among participants, particularly Hispanic and African-American subjects, with systolic blood pressures between 140 and 150 mm Hg.
Compared with people who have lower systolic blood pressure, those whose levels exceed 140 mm Hg—a range that encompasses a group of patients ineligible for treatment based on the JNC8 recommendations—had a significantly increased risk of stroke, report investigators.
“When JNC8 came out with its revised recommendations to lift the threshold for systolic blood pressure from 140 mm Hg to 150 mm Hg in people over the age of 60 without diabetes or chronic kidney disease, we were concerned,” senior investigator Ralph Sacco, MD, of the University of Miami in Florida, told TCTMD. “As a stroke-prevention physicians, we know that high blood pressure is the single leading modifiable risk factor for stroke. We were concerned that changing the threshold for systolic blood-pressure treatment would be very deleterious for stroke risk.”
The new data, derived from a subset of participants enrolled in the observational Northern Manhattan Study (NOMAS), showed that compared with individuals who had a systolic blood pressure of less than 140 mmHg, those with blood pressure between 140 and 149 mm Hg had a 72% increased risk of stroke. The increased risk was even more pronounced among Hispanic and non-Hispanic black individuals.
Results of the study were published February 1, 2016, in Hypertension.
Controversy Followed JNC8 Publication
The December 2013 publication of recommendations from JNC8 on the prevention, detection, evaluation, and treatment of high blood pressure saw the committee relax blood-pressure targets in elderly patients and in younger patients with diabetes and chronic kidney disease. For elderly patients, those 60 years and older, the JNC8 writing group now recommends starting treatment if systolic blood pressure is 150 mm Hg or higher (or ≥ 90 mm Hg diastolic blood pressure) and to treat to under those targets.
When JNC8 was published, Sacco said he and others were concerned about the implications of shifting the treatment threshold, specifically for Hispanic and African-American individuals, a subgroup of the population that “have some of the greatest risks for stroke and the greatest prevalence of uncontrolled high blood pressure.”
In NOMAS, the researchers studied 1,750 individuals 60 years of age and older without stroke, diabetes, or chronic kidney disease. Just under half of participants included were Hispanic, while non-Hispanic white and non-Hispanic black participants were equally represented and made up the rest of the cohort. Overall, 43% of participants had systolic blood pressure < 140 mm Hg, 20% were in the 140-to-149 mm Hg range, and 37% had systolic blood pressure ≥ 150 mm Hg. During the 13-year follow-up period, there were 182 incident strokes, including 159 ischemic and 18 hemorrhagic events.
After adjustment for multiple risk factors, individuals with systolic blood pressure between 140 and 149 mm Hg—which is below the current JNC8 threshold for starting therapy—had a significantly increased risk of stroke. “Our study shows that a systolic blood pressure of 140 to 149 [mm Hg] is probably just as bad as blood pressure greater than 150 [mm Hg] for this population,” said Sacco.
The relaxing of treatment thresholds by JNC8 was controversial and not supported by other professional organizations. In fact, support for increasing the start-treatment threshold wasn’t even unanimous among the JNC8 members, with 5 physicians later speaking out against the decision to shift from 140 to 150 mm Hg in people 60 years and older.
European guidelines currently recommend all patients be treated to a target of less than 140 mm Hg while the American Society of Hypertension only recommends a start-treatment threshold of 150 mm Hg or greater in those 80 years and older. The American Heart Association, the American College of Cardiology, and Centers for Disease Control recommend a blood-pressure goal of less than 140 mm Hg (with ideal blood pressure defined as less than 120/80 mm Hg).
SPRINT Moves the Goalposts Again
Just a few months ago, the SPRINT investigators shook up the field of hypertension when they published their landmark results showing significantly lower rates of cardiovascular events and all-cause mortality among high-risk hypertensive patients who achieved a systolic blood-pressure goal of 120 mm Hg. In more than 9,000 patients with hypertension but without diabetes, those who achieved the low target had a 25% lower risk of cardiovascular events vs those with a target of less than 140 mm Hg. Those who achieved that target also had a 27% lower risk of all-cause mortality and a 43% lower risk of cardiovascular death.
Sacco said SPRINT adds yet more randomized clinical trial evidence showing that lower and more tightly controlled systolic blood pressure is better for patients. In SPRINT, unlike in their analysis, the reduction in stroke was not significant with lower achieved blood pressure, although he notes the trial was stopped early because of the clear advantage seen for lowering to less than 120 mm Hg.
While the guidelines are expected to change on the heels of SPRINT, Sacco recommends treating all patients 60 years of age and older without diabetes and chronic kidney disease if their systolic blood pressure exceeds 140 mm Hg. For younger patients, based on SPRINT, treating to a systolic blood pressure of 120 mm Hg is “probably where we need to go,” he said.
To TCTMD, Sripal Bangalore, MD, of the New York University School of Medicine, noted that the mean age of patients in the NOMAS analysis was 72 years, which was older than the patients in SPRINT. The SPRINT trial did include a large number of older patients, with 28% of the population aged at least 75 years and the benefit of 120 mm Hg being observed here, too.
Regarding the NOMAS analysis, Bangalore said the evidence of benefit with lower systolic blood pressure is not surprising, especially in light of the positive SPRINT data. While the start-treatment thresholds in JNC8 are controversial, he agreed, the publication of SPRINT has shifted physicians attention to even lower thresholds than those compared in NOMAS.
The new analysis does provide a consistent message, however, in that there is a beneficial reduction in stroke with lower systolic blood pressure. Bangalore, who was not affiliated with the NOMAS analysis, said that despite results showing lower is better when it comes to systolic blood pressure, treatment needs to be individualized. While physicians are pushing levels lower, they can be content with higher blood pressure if the patient is substantially older/frail and might be at risk of falls. “There are a lot of factors to consider, such as how much medication they’re on, and what we’re trying to reduce, and what the risk of adverse outcomes might be,” said Bangalore.
Dong C, Della-Morte D, Rundek T, et al. Evidence to maintain the systolic blood pressure treatment threshold at 140 mmHg for stroke prevention. Hypertension. 2016;Epub ahead of print.
- SPRINT Makes the Case for Even Lower BP Target in Many Hypertensive Patients
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Michael O’Riordan is the Associate Managing Editor for TCTMD and a Senior Journalist. He completed his undergraduate degrees at Queen’s…
- The study was supported by a grant from the National Institute of Neurological Disorders and Stroke and the National Center for Advancing Translational Sciences.
- Bangalore reports having no conflicts of interest.