Experts Agree: Lower Blood Pressure Is Better, but What’s a Realistic Target?

A new observational study supports the SPRINT trial finding that getting systolic blood pressure below 120 mm Hg cuts cardiovascular risk compared with adhering to more relaxed goals, but questions remain about whether it’s realistic to aim for such low targets routinely. Indeed, only an estimated 11.9% of hypertensive adults in this Korean analysis achieved levels that low, albeit at a time before the SPRINT results were known.

“Practically, getting SPRINT-defined BP goals in everyday practice is not easy, particularly since the target BP was not reached in more than half of the participants in the intensive-treatment group even in the SPRINT trial,” senior author Duk-Woo Park, MD, PhD (Asan Medical Center, Seoul, South Korea), told TCTMD in an email.

But Paul Whelton, MD (Tulane University School of Public Health and Tropical Medicine, New Orleans, LA), who is chair of the SPRINT steering committee, told TCTMD that getting patients down to below 120 mm Hg is feasible.

“In practice if you’re careful about the blood pressure measurements and you choose the right medications and the right combinations and go to full dose . . . and you work with participants to be sure that they’re taking the medications and so on, you can actually control blood pressure very well,” he said.

It remains to be seen, however, how the SPRINT results will be incorporated into comprehensive hypertension guidelines currently being developed by the American Heart Association (AHA) and American College of Cardiology (ACC), with an expected release of late 2016 or early 2017.

There has been controversy in recent years because of conflicting blood pressure targets in various guidelines. A group of experts initially empaneled as the Eighth Joint National Committee (JNC 8) released recommendations in December 2013 that relaxed blood pressure goals for many patients compared with the JNC 7 guidance. They recommended a target of 150/90 mm Hg for adults 60 and older who do not have chronic kidney disease or diabetes and a goal of 140/90 mm Hg for younger patients and those with chronic kidney disease or diabetes. The document, which was created with a focus on randomized trial evidence, sparked heated debate and was not ultimately backed by any major organization.

To TCTMD, Jackson T. Wright Jr., MD, PhD (University Hospitals Case Medical Center, Cleveland, OH), a member of the SPRINT steering committee and of the JNC 8 panel, said the trial’s results render that controversy moot, noting that Hypertension Canada has already incorporated the target systolic blood pressure of 120 mm Hg or less for selected high-risk patients.

Moving forward, “it will be very hard for any guideline to justify less than 150 [mm Hg as a treatment target],” said Wright, who is participating in creation of the AHA/ACC guidelines. “It will be very hard now for guidelines to justify less than 140 as a target, so it certainly will be somewhat lower than 140.”

In the meantime, said Whelton, who is chair of the AHA/ACC guidelines committee, “clinicians should use their judgment.”

To that point, Park said, “I think that beyond the BP target per se, several important factors are considered to inform decision-making for BP-lowering therapy in the contemporary medical setting—for instance, an integrated and systematic assessment of combined risk factors and baseline cardiovascular risk, concomitant preventive medical therapies, clinician-patient discussions of the potential benefits and harms, or the clinical judgment of the treating physicians.”

Other SPRINT-Like Studies Needed

In the study, published online ahead of the June 21, 2016, issue of the Journal of the American College of Cardiology, Park along with lead author Min Jung Ko, PhD (National Evidence-based Healthcare Collaborating Agency, Seoul, Korea), and colleagues examined cardiovascular risk as it relates to the discrepant blood pressure targets used in the SPRINT trial and recommended in the JNC 8 document.

They used data on 13,346 hypertensive patients participating in the Korean National Health and Nutrition Examination Survey (KHANES) between 2008 and 2013 and on 67,965 patients included in the Korean National Health Insurance Service (NIHS) health examinee cohort of 2007.

Using the KHANES data, the researchers estimated that only 11.9% of hypertensive Korean adults would achieve a systolic target of less than 120 mm Hg, whereas 70.8% would meet the less strict JNC 8 targets.

Ten-year predicted cardiovascular risk according to Framingham score was lowest in patients achieving the SPRINT goal (6.15%), intermediate in those between the SPRINT and JNC 8 goals (7.65%), and highest in those above the JNC 8 goals (9.39%; P < 0.001).

The investigators then calculated actual event rates during a mean follow-up of 6.6 years in the NIHS cohort. After multivariate adjustment, there was a significant trend (P < 0.001) toward a higher risk of major cardiovascular events (MI, stroke, or cardiovascular death) as blood pressure increased. Similar patterns were seen for MI and stroke individually, but not for cardiovascular or all-cause mortality.

Whelton, who co-authored an accompanying editorial with Paul Muntner, PhD (University of Alabama at Birmingham), said there was nothing surprising about the findings and indicated that the study highlights the need to conduct SPRINT-like studies in diverse populations to validate the results. He noted that, in contrast to the United States, Korea tends to have more nonischemic cardiovascular disease.

“Don’t always depend on what’s done in the US and what’s done in Europe because our systems of treatment are different, our cultures are different, [and] our patterns of cardiovascular disease are different,” he said.

Is Extra Effort Worth It?

Park and colleagues point out that a more aggressive and time consuming approach would be needed to start bringing systolic blood pressures down to less than 120 mm Hg.

Wright said that “most hypertensives can be reasonably treated to less than 120 and that includes even those patients over age 75.” Important considerations in doing so include more careful measurement of blood pressure than is typical in everyday practice and the fact that patients needed, on average, one additional medication (three instead of two) to reach the lower goal in SPRINT.  

But Paul James, MD (University of Iowa, Iowa City), who co-chaired the JNC 8 panel, urged caution as the SPRINT results are incorporated into clinical practice. “I do think people are jumping the gun on what new blood pressure goals should be,” he said.

The most prudent approach to cardiovascular prevention should be worked out by a group made up of relevant stakeholders, he told TCTMD. That would include not only the AHA and ACC, but also consumer and patient advocates, representatives from primary care and geriatrics, payers, and cost-effectiveness and health services researchers, he said.

He said that there is a legitimate question about whether patients would be willing to take an average of three medications to reduce their risk of cardiovascular events by an absolute 1.6% over about 3 years.

“I think for some people absolutely it is the right thing,” James said. “I think for other people it is not necessarily.”

It comes down to a value decision that incorporates patient preference, other morbidities, and cost, he said, pointing out that based on the SPRINT results, a thousand patients would have to be treated to the lower goal versus the standard goal of less than 140 mm Hg to have 16 people benefit.

“I’m just concerned that when we start making the majority of the population ‘sick’ with prediabetes and prehypertension that needs to be treated with medications that we may be missing the boat on some underlying preventive health measures,” he said. Cardiovascular risk can also be reduced, James added, by ensuring that people are staying active, reducing salt intake, losing weight, and eating a healthy diet.

 

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