Researchers at the University of Tennessee Health Science Center and the Memphis Veterans Affairs Medical Center played a significant role in collecting data that resulted in the new guidelines announced last week for the prevention, detection, evaluation, and management of high blood pressure.
The first comprehensive new high blood pressure guidelines in more than a decade were published by the American College of Cardiology and the American Heart Association at the association’s 2017 Scientific Sessions Conference in California. They set the definition of hypertension or high blood pressure at 130/80 mm Hg, rather than 140/90. The significant reduction is based on results from the SPRINT (Systolic Blood Pressure Intervention Trial) study, which took place at 102 study sites across the country, including sites at UTHSC and the Memphis VA.
The study “changed the way we define high blood pressure,” said Karen C. Johnson, MD, MPH, College of Medicine Endowed Professor in Women’s Health at UTHSC. Dr. Johnson was the national vice chair of the SPRINT Steering Committee and the principal investigator for the study site at UTHSC.
“I think that it will result in a huge reduction in cardiovascular disease and death, when people start using these new levels in practice,” she said.
The SPRINT study was a randomized clinical trial begun in the fall of 2009. It included more than 9,300 participants, age 50 and older, recruited from more than 100 medical centers and clinical practices throughout the United States and Puerto Rico. It was the largest study of its kind to date to examine how maintaining systolic blood pressure at a lower than the then-recommended level would impact cardiovascular and kidney diseases. The large UTHSC site recruited and followed 176 subjects, and the Memphis VA site recruited and followed 80 participants.
In 2015, the National Heart, Lung, and Blood Institute, which sponsored SPRINT, stopped the national study about a year earlier than planned in order to disseminate the significant preliminary results.
SPRINT found that more intensive management of high blood pressure, below the commonly recommended blood pressure target, significantly reduced rates of cardiovascular disease and lowered risk of death in adults 50 years and older with high blood pressure. The intervention adjusted the amount or type of blood pressure medication to achieve a target systolic pressure below 120 millimeters of mercury (mm Hg). This reduced rates of cardiovascular events, such as heart attack and heart failure, as well as stroke, by a quarter, and the risk of death by more than a quarter, as compared to the target systolic pressure of 140 mm Hg.
Dr. Johnson explained the new guidelines set normal blood pressure as less than 120 over 80. Elevated blood pressure is now considered to be in the 120-129 range (systolic). Stage 1 hypertension is at 130 to 139. “That’s a big change, because it used to be 150 (systolic),” she said.
The new guidelines should encourage people to get their blood pressure checked and to monitor their levels, just as they do blood sugar levels for diabetes.
“You need to get your blood pressure rechecked, because you want to make sure that if you have high blood pressure, you have it treated to less than 130, and I personally, think you should have it less than 120, based on the SPRINT study,” she said.
“The SPRINT clinical trial was an amazing project,” said Catherine Womack, MD, co-division chief of General Internal Medicine, interim chair of Preventive Medicine, and coinvestigator for the study at UTHSC. “Basically, we were able to prove that lower blood pressure prevents heart attack and all-cause mortality in older patients with hypertension. Based on our investigative findings, the national blood pressure guidelines lowered the blood pressure levels needed to diagnose hypertension. It is not often that an investigator can say they changed the way doctors practice medicine. I am very proud to have worked with Dr. Johnson and all the other investigators on this important clinical trial.”
The new guidelines not only base blood pressure treatment goals on SPRINT, but also stress how important it is to measure blood pressure correctly, as was done in SPRINT, said William C. Cushman, MD, chief of Preventive Medicine at the Memphis VA, and professor of Preventive Medicine, Medicine, and Physiology at UTHSC. Dr. Cushman was the principal investigator for the VA Network of 25 VA sites, which recruited 1,660 participants for the trial.
Linda Nichols, PhD, professor, and Jennifer Martindale-Adams, EdD, associate professor, in the Department of Preventive Medicine at UTHSC, are coinvestigators for the VA Network on another portion of the study, SPRINT MIND, which is looking at whether lower blood pressure decreases risk of cognitive impairment. That portion of the study is ongoing.
Dr. Johnson said SPRINT has had a worldwide impact on how people define hypertension. “That’s huge,” she said. “And now we just need to get clinicians to follow the guidelines.”