Getting that top number, called the systolic blood pressure, under 120, however, does not provide additional health benefits, according to the study published in June.
“If you have high blood pressure, then getting your systolic blood pressure below 140 provides benefits in terms of reducing the risks of cardiovascular events such as heart attack, heart failure, stroke and death,” said the study’s lead researcher, Carlos J. Rodriguez, M.D., M.P.H., associate professor of epidemiology and medicine and associate director of research at the Maya Angelou Center for Health Equity at Wake Forest School of Medicine. “And if you’re African-American, the degree of benefit is even greater.”
Willie E. Lawrence, Jr. M.D., a spokesman for the American Heart Association and chief of cardiology at Research Medical Center in Kansas City, Missouri, believes the study’s results are positive for the treatment of hypertension.
“This study helps substantiate that hypertension is really not a complicated thing,” Dr. Lawrence said. “Get people’s blood pressure to less than 140/90 (mm Hg). This is not confusing news. It does not represent a change from our recent recommendations.”
Dr. Lawrence worked with other experts from the AHA, the American College of Cardiology and the Centers for Disease Control and Prevention to draft the latest joint scientific advisory about hypertension. It was released last year.
The study’s results don’t lead Dr. Lawrence to believe any change needs to be made in the way people with high blood pressure are currently treated.
“We do such a horrible job of getting people down to 140/90,” he said, therefore there is very little issue with doctors over treating patients to get their systolic pressure below 120.
Dr. Lawrence made the distinction that lowering systolic blood pressure further to 120 through lifestyle changes is different than if it is achieved through additional medications, which may come with unwanted side effects.
“If I was hypertensive and obese and I got on an exercise program, worked on my diet and got my blood pressure lower, there may be a greater benefit than if I got there through medication alone.”
The study looked at data from 4,480 people who had already been diagnosed with high blood pressure—also known as hypertension—a disease that strikes one in three U.S. adults.
Researchers culled through data from the Atherosclerosis Risk in Communities study which signed up participants from 1987 through 1989 and recorded their results every three years at three different times.
“If you have high blood pressure, discuss with your doctor how best to manage it,” said Dr. Rodriguez. “Our study supports the current guidelines and it really shows that the guidelines work for most people.”
Dr. Rodriguez said the results weren’t exactly what he expected. “I was surprised because we thought we would see lower cardiovascular events with lower blood pressure. The benefit plateaus once the blood pressure gets below 140,” he said.
The study reported that:
- During the study period, 1,622 cardiovascular events occurred.
- Participants with high systolic blood pressure had a significantly higher rate of cardiovascular events.
- The rate of heart attacks, strokes, death and other cardiovascular events was highest in the group whose top number was higher than 160.
- African-Americans had the highest difference in cardiovascular events when comparing the highest and lowest systolic blood pressure groups. This, researchers said, suggests that African-Americans were more likely to have a greater benefit from achieving systolic blood pressure levels below 140 than any other group.
- People in the group with the highest blood pressure were more likely to be male and African-American and somewhat more likely to have diabetes.
Dr. Rodriguez said the study’s results can be applied to a large portion of the U.S. population because it included patients from various locations in the country: Forsyth County, North Carolina; Jackson, Mississippi; suburban Minneapolis; and Washington County, Maryland.
He believes further questions will be answered in a few years when the results are released from a nine-year National Institutes of Health clinical trial dubbed SPRINT. That trial is rigorously comparing using medications to either get patients’ systolic blood pressure to less than 140 or down to less than 120.