AHA.15: SPRINT trial finds lowering systolic blood pressure target improves outcomes

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For adults who were at least 50, with an increased risk of cardiovascular events and who did not have diabetes, reducing the systolic blood pressure target to less than 120 mm Hg led to lower rates of fatal and nonfatal major cardiovascular events and death from any cause compared with the standard target of less than 140 mm Hg.

These findings, from the SPRINT (Systolic Blood Pressure Intervention Trial) study, were presented on Nov. 9 at the American Heart Association (AHA) Scientific Sessions and simultaneously published online in the New England Journal of Medicine.

“Overall, we deem that the benefits [of lowering the target to less than 120 mm Hg] far outweigh the potential for risk,” Paul K. Whelton, MD, chairman of the SPRINT steering committee, said at a news conference. Current guidelines recommend a systolic blood pressure of less than 140 mm Hg for healthy adults and 130 mm Hg for adults with kidney disease or diabetes.

Adults in the intensive treatment group, which targeted 120 mm Hg, had a 25 percent lower relative risk of the primary composite outcome of MI, other acute coronary syndromes, stroke, heart failure or death from cardiovascular causes compared with the standard treatment group. They also had a 38 percent lower relative risk of heart failure, 43 percent lower relative risk of death from cardiovascular causes and 27 percent lower relative lower risk of death from any cause.

However, rates of serious adverse events such as hypotension, syncope, electrolyte abnormalities and acute kidney injury or failure were higher in the intensive treatment group.

The National Institutes of Health, which sponsored the trial, released preliminary results of the SPRINT trial in September. Based on the findings and a recommendation from the data and safety monitoring board, the researchers stopped the trial early on Aug. 20 after a median follow-up of 3.26 years. Whelton said they expected to follow participants for a mean of five years.

In the SPRINT study, researchers enrolled 9,361 adults between November 2010 and March 2013 and randomized them to the standard target of less than 140 mm Hg or the intensive target of 120 mm Hg. The trial took place at 102 sites in the U.S. and included participants who were at least 50, had a systolic blood pressure of between 130 mm Hg and 180 mm Hg and an increased risk of cardiovascular events. Adults with diabetes, prior stroke or polycystic kidney disease were excluded.

After one year, the mean systolic blood pressure was 121.4 mm Hg in the intensive treatment group and 136.2 mm Hg in the standard treatment group. During the follow-up period, the mean systolic blood pressure was 121.5 mm Hg and 134.6 mm Hg, respectively.

The rate of the primary composite outcome was 1.65 percent per year in the intensive group and 2.19 percent per year in the standard group. Deaths occurred in 155 adults in the intensive group and 210 adults in the standard group.

For the intensive group, the number needed to treat to prevent one primary outcome event was 61 and the number needed to treat to prevent one death from any cause was 90.

“Taking the whole picture together, this is an amazing triumph,” Marc A. Pfeffer, MD, of Brigham & Women’s hospital in Boston, said at a news conference. “We have to thank the participants and thank the government for all the things they’ve done.”

The researchers mentioned that only approximately 50 percent of the U.S. population have a blood pressure of less than 140/90 mm Hg, so it may be difficult to get people’s systolic blood pressure below 120 mm Hg. In this study, more than half of patients in the intensive group had a systolic blood pressure above 120 mm Hg. The mean number of blood pressure medications was 2.8 in the intensive group and 1.8 in the standard group.

“These observations suggest that achieving a systolic blood pressure goal of less than 120 mm Hg in the overall population of patients with hypertension would be more demanding and time-consuming for both providers and patients than achieving a goal of 140 mm Hg, and would necessitate increased medication costs and clinic visits,” the researchers wrote.

Participants could take any of the major classes of antihypertensive agents and were seen monthly for the first three months and every three months for the remainder of the study. Researchers also collected clinical and laboratory data at baseline and then every three months and conducted structured interviews every three months.

Serious adverse events occurred in 38.3 percent of the intensive group and 37.1 percent of the standard group, while serious adverse events that were classified as possibly or definitely related to the intervention were found in 4.7 percent and 2.5 percent of participants, respectively.

“I think [the results are] certainly going to shift my approach, but it’s hard enough to get people to be on antihypertensives as is,” Pfeffer said. “That’s why I was stressing the doctor isn’t going to get a thank you, the patient isn’t going to say ‘Another medicine?’ because that makes people feel they’re sicker than they were. We need a lot of education here, but I think if we do that, we’ll be lowering cardiovascular morbidity [and] mortality.”