Decreasing blood pressure below current standards can indeed save lives and prevent more heart attacks, researchers confirmed Monday.
Last September, a government-led team of experts created an uproar among heart disease experts when they stopped an ongoing study of blood pressure treatment to announce that patients who got more drugs to force their blood pressure lower were living longer and suffering fewer heart “events” such as heart attacks and strokes.
But they didn’t have all the details yet. Now, they’ve released them at a meeting of the American Heart Association. And the details stand up.
For blood pressure patients 50 and older, going for a reading of 120 millimeters of mercury (mm Hg) cuts events such as heart attack, stroke and heart failure by 25 percent. And people whose blood pressure was forced this low were 27 percent less likely to die over the three-year study than people whose blood pressures were at the current target of 140.
A third of U.S. adults have high blood pressure so millions could be affected by the findings.
It was these findings that stunned the researchers and promoted a stop to the study so they could dig into the numbers.
“When the benefits of the stronger intervention became apparent in SPRINT, we made a commitment to rapid public health communication and peer-reviewed publication of the study results,” said Dr. Gary Gibbons, director of the National Heart, Lung, and Blood Institute (NHLBI), which sponsored the study.
The findings held up, the team told the meeting.
"Regardless of whether the patients had cardiovascular disease or not, had kidney disease or not, were black or white, male or female, or above or below age 75 — all appeared to benefit similarly," Dr. Jackson Wright Jr., a blood pressure expert at Case Western Reserve University, told NBC News.
Right now, people are told to get their blood pressure to 140 or lower. That's the top number in a blood pressure reading, known as systolic blood pressure.
It took, on average, three drugs to get a patient's blood pressure down to 120 — usually a diuretic, the first-line choice for lowering blood pressure, plus a drug called a calcium channel blocker and one called an ACE inhibitor. There are many choices within these classes of drugs. Each lowers blood pressure by a different mechanism.
Dr. Donald Lloyd-Jones of Northwestern University in Chicago, who was not involved in the study, welcomed the news. “This is a game-changer for many, but not all,” he told NBC News. He said he’ll look at working harder to get blood pressure lower in his healthy patients over 50.
Certain bad side-effects became more common as blood pressure went lower. They include low blood pressure, fainting, abnormalities in compounds called electrolytes, and acute kidney damage.
But the researchers said people were not more likely to fall or suffer harmfully slow heart rates, and those with kidney disease did not see their condition worsen.
“The benefits of more intensive blood pressure lowering exceeded the potential for harm, regardless of gender or race/ethnicity,” said Dr. Paul Whelton of Tulane University School of Public Health and Tropical Medicine, who helped lead the study.
But they’re still following up to see if rates of dementia or other types of cognitive impairment might be different with lower blood pressure. Some studies have found some people have trouble thinking if they take too much blood pressure medication.
Cleveland Clinic’s Dr. Steve Nissen said more analysis is needed, and predicted a great deal of “discussion”.
“I always worry that a rush to judgment, that an irrational exuberance will lead to over-treatment of people,” Nissen told NBC News.
“We don't want to under-treat, and we don't want to ignore these results but we want to understand these results better before we change practice across the country.”
Questions that need to be answered:
- Is it OK to get blood pressure to, say, 130?
- When do the benefits kick in between 120 and 140?
- Is it worth taking more drugs to get blood pressure lower?
“It’s also important to remember that healthy lifestyle changes can make a difference in controlling high blood pressure,” said NHLBI’s Dr. Lawrence Fine.
The American Heart Association and the American Medical Association announced a joint initiative Monday to focus more attention on blood pressure.
“There is a substantial body of evidence showing that high blood pressure is a contributing factor to many major health conditions, including heart attack, heart failure, stroke, kidney failure and other disease consequences,” the Heart Association said.
A new target could be even harder to hit than the current blood pressure target.
“Currently, only about half of Americans with high blood pressure are achieving our recommended blood pressure reading of below 140/90 mm Hg,” said Heart Association president Dr. Mark Creager, director of the Heart and Vascular Center at Dartmouth-Hitchcock Medical Center.