Confused about how low your blood pressure should be? That’s understandable, considering the headlines that a major study generated recently.
The study, dubbed the Systolic Blood Pressure Intervention Trial, or SPRINT, suggests that a blood pressure level that is much lower than what is currently recommended for some people can significantly cut the risk of heart failure and death from heart problems. But many experts, including those at Consumer Reports Best Buy Drugs, say it’s unknown whether the SPRINT findings are relevant for most people with high blood pressure. That’s because the study looked only at a small, high-risk subset of people with hypertension.
If you’ve received a hypertension diagnosis, it’s important to keep your blood pressure at a healthy level. In the United States, uncontrolled high blood pressure leads to more heart attacks and strokes than any other cause. But how low is low enough?
Under current guidelines, the ideal is a systolic pressure (top number) of 120 millimeters of mercury or less, and a diastolic pressure (bottom number) of 80 or less. You’re considered to have high blood pressure if the systolic hits 140 or the diastolic goes to 90 or above. But experts have long debated whether those with high blood pressure need to get their levels all the way down to the ideal.
The SPRINT study sought to end this debate, and at first glance the results suggest that lower is healthier. Here’s why: The trial involved more than 9,300 people with elevated blood pressure and a high risk of heart attack. They were given medication to reduce their blood pressure. About half aimed to lower their systolic pressure to 120; the other half had a goal of 140.
The study had been slated to run for five years, but it was stopped after slightly more than three years because results were so dramatic. During that time, 65 people in the group aiming for a systolic pressure of 140 died and 100 developed heart failure. Of those trying to get down to a systolic of 120, only 37 died and 62 developed heart failure, researchers reported in the New England Journal of Medicine.
Gary Gibbons, director of the National Heart, Lung, and Blood Institute (NHLBI), SPRINT’s primary sponsor, says the findings will change high blood pressure treatment and save lives.
But the benefits came with significant downsides. To get down to 120, people in the study had to take three blood pressure medications, on average.
That led to almost double the instances of serious side effects, including some that required emergency care at a hospital, such as kidney failure, dangerously low blood pressure and imbalances in potassium or sodium blood levels.
Also, many people find it difficult to take their blood pressure medication consistently, and an additional pill may increase that challenge, notes Michael Pignone, chief of internal medicine at the University of North Carolina School of Medicine in Chapel Hill. In fact, because of side effects, the need to cut costs and/or other factors, up to half of people stop taking their hypertension medication within a year of starting on it. “Putting somebody on more medications if they’re not consistently taking their current regimen is not a helpful strategy,” Pignone says.
SPRINT focused on a specific group of people with hypertension: those 50 and older with at least one other chronic condition, such as heart disease or kidney disease (both of which raise heart attack and stroke risks), and those 75 and older. Of every six people with high blood pressure, only about one of them is in such a high-risk group.
If you are in that group, talk with your doctor about whether lowering your systolic blood pressure to 120 is worth the risk, says Harlan Krumholz, a cardiologist at Yale University. If you’re not in that group, based on these new findings, you may not need to aim for such a low number.
Also talk with your doctor about making lifestyle changes that can help reduce blood pressure. Those are especially important for people like those in the group studied in SPRINT.
If you’re not in one of the previously mentioned high-risk categories, what should your blood pressure be? Consumer Reports’ medical experts consider 150/90 a reasonable goal for most people age 60 to 75 who don’t have other risk factors. They suggest a goal of 140/90 for people younger than 60, those with diabetes and those younger than 50 with chronic kidney disease.
Those numbers are based on recommendations from an independent expert panel convened by the NHLBI. The panel noted that achieving levels below 140/90 can require additional blood pressure drugs or high doses. That increases the risk of the previously mentioned side effects and — depending on the drugs — problems such as persistent coughing, erectile dysfunction and frequent urination.
Uncertain about your blood pressure? Get it measured, even if you think it’s fine. The U.S. Preventive Services Task Force recommends that everyone 18 and older be screened for hypertension. Having high blood pressure generally causes no obvious symptoms, so an estimated one-fifth of American adults with the problem don’t know they have it.
Surprisingly, the most accurate way to measure your blood pressure is not at your doctor’s office. Up to 30 percent of people receive an incorrect diagnosis of high blood pressure, often because their blood pressure is normal at home but spikes in a doctor’s office, perhaps because of anxiety. Blood pressure can also fluctuate depending on such factors as sitting position, bladder fullness and placement of the monitor’s cuff.
The gold standard for measuring blood pressure — a method known as ambulatory monitoring — involves wearing a small, doctor-prescribed device that records your blood pressure at frequent intervals over 24 hours. But that monitoring isn’t widely available, and insurance might not cover the cost. A good alternative, the task force says, is a home blood pressure monitor. Record levels once in the morning and once in the evening for a week.
For further guidance, go to www.ConsumerReports.org/Health, where more detailed information, including CR’s ratings of prescription drugs, treatments, hospitals and healthy-living products, is available to subscribers.