Photo of blood pressure monitor on a person's arm

NIH’s SPRINT trial played a key role in the evolution of the new blood pressure guidelines

Health experts are calling the recent release of new blood pressure guidelines a major step toward helping Americans reduce their risk of heart disease, the leading cause of U.S. deaths. Developed jointly by the American Heart Association (AHA) and the American College of Cardiology (ACC), the guidelines now define hypertension as a systolic blood pressure of 130 millimeters of mercury (mm Hg) or higher, rather than 140 mm Hg or higher. Importantly, the guidelines emphasize lifestyle changes—heart-healthy diets, weight loss, and exercise—as a key first step for many Americans trying to reach the lower blood pressure target. 

Researchers at the National Institutes of Health (NIH) had a strong interest in the new guidelines, and for good reason: For decades the NIH has funded numerous studies aimed at finding ways to prevent heart disease. But a landmark NIH study called SPRINT (Systolic Blood Pressure Intervention Trial), released in 2015, provided critical insights into the effect a lower blood pressure target had on reducing heart disease risk.

The SPRINT evidence was compelling and, as it turns out, informed the new AHA/ACC guidelines. SPRINT found that a blood pressure target of less than 120 mm Hg could save lives, particularly among older, high-risk individuals with high blood pressure.  The new guidelines underscore the crucial importance of keeping one’s blood pressure well below the previous target of less than 140 mm Hg. In doing so, say those involved in SPRINT, they could help propel a reduction in heart disease in this country.

“We’re excited,” said Lawrence Fine, M.D., Chief of the Clinical Applications and Prevention Branch at the National Heart, Lung, and Blood Institute (NHLBI), the primary sponsor of the four NIH Institutes funding SPRINT. “The new guidelines are comprehensive, and they address important questions that patients have about how best to treat their high blood pressure. We look forward to seeing these guidelines adopted into clinical practice and thus aid in the further prevention of cardiovascular disease.” 

It was 2009 when researchers began debating about the optimal goal for blood pressure treatment. The SPRINT trial was launched to answer the question of whether a blood pressure level of less than 120 mm Hg would reduce the risk of heart disease, compared to a level of less than 140 mm Hg. The trial recruited more than 9,300 adults aged 50 and older at risk for cardiovascular disease from 102 medical centers and clinical practices throughout the United States, becoming the largest trial to test these two blood pressure goals.

The results provided a major contribution to hypertension research.  SPRINT showed that achieving the lower blood pressure goal of 120 mm Hg (instead of 140 mm Hg) reduced the rate of cardiovascular events by about 25 percent and the overall risk of death by 27 percent. The results were so positive—and conclusive—that the NIH stopped the SPRINT intervention early, after a little over three years of follow-up, and disseminated the findings, which were quickly published in the New England Journal of Medicine.

“SPRINT was an important trial for clinicians and patients with hypertension, particularly in terms of its remarkable reduction in major cardiovascular disease events and all-cause mortality,” said Paul Whelton, M.D., Chairman of Global Public Health at Tulane University School of Public Health and Tropical Medicine, who also was Chair of the SPRINT trial and the AHA/ACC guideline writing committee. “The SPRINT study findings have had a significant influence on the new guidelines,” Whelton added.  “They convincingly showed that a lower blood pressure goal results in better health for many patients with high blood pressure.” 

But SPRINT was hardly the only factor behind the updated guidelines. Experts on the AHA/ACC guideline writing committee engaged in a comprehensive three-year process of reviewing hundreds of research studies related to the diagnosis, prevention, and management of blood pressure. They also considered a host of other factors related to patients with or at risk for hypertension, including age, race, gender, co-existing medical conditions, and available blood pressure medications.  

“At the end of the day, a guideline is not based on one study alone,” explained NHLBI’s Fine, who is also one of the co-authors of the SPRINT study. “It’s based on input from multiple studies, with the goal of improving the health of patients. Good guidelines should inform clinical practice but do not replace shared decision-making between a patient and a clinician.”

Now that the new guidelines have been established and shared, the next big challenge is implementing them. Health professionals say this will not be an easy task, considering that almost half of all adults will now be reclassified as having high blood pressure, compared to nearly a third under the previous guidelines.

The new guidelines emphasize lifestyle changes as a way for many to reach the lower blood pressure target. That generally means heart-healthy diets, weight loss (among those overweight or obese), and increased levels of exercise, according to the recommendations. For some adults with high blood pressure, experts recommend a regimen of anti-hypertension drugs.

“Putting guidelines into real-world practice is the Achilles heel of delivering high-quality care,” said George Mensah, M.D., Director of the Center for Translation Research & Implementation Science at NHLBI. “How do we make it easier for doctors, nurses, and patients to follow the guidelines? What decision-support tools can aid health care providers? How can we support patients and their families to follow what the guidelines recommend? At NHLBI, we remain committed to pursuing research to answer these types of questions now and in the future.”

Still, the guidelines are not set in stone. As new research findings and technologies emerge, clinical recommendations can change.  To ensure that the new guidelines remain current, the AHA/ACC will review new clinical research data on an ongoing basis, with a full guideline review expected to take place about every six years.