A doctor talking to a male patient.

Millions of Americans may want to talk to their doctors about whether or not they need medication to reduce their risk of cardiovascular disease, according to a new study published in the Annals of Internal Medicine.

The study, led by Stanford University researchers, found that the heart disease and stroke risk calculators doctors currently use may significantly overestimate some people’s risk and also underestimate others' risk.

As a result, many people may be unnecessarily taking medication to control risk factors such as high cholesterol and high blood pressure, and others, notably African-Americans, may not be getting enough treatment.

Some previous studies have suggested that traditional risk calculators, particularly the ACC/AHA ASCVD Risk Calculator developed by the American College of Cardiology and the American Heart Association in 2013, may overestimate risk. To remedy that, these researchers developed a new risk calculation method with a more sophisticated statistical model and newer population data than existing calculators, and they suggest that it may be more accurate.

More On Heart Health

Some other experts agree. Though it's not quite ready for wide usage yet, “this has high potential to be a breakthrough in being able to much more accurately predict cardiovascular disease risk,” says Andrew DeFilippis, M.D., M.Sc., assistant professor in the department of medicine at the University of Louisville in Kentucky, who co-authored an editorial accompanying the study.

Here’s what you need to know about this new research, the drawbacks of current heart risk calculators, and what to ask your doctor now.  

What the New Study Found

Heart risk calculators are fairly simple: Your doctor (or you) enter information online, such as your age, gender, blood pressure and cholesterol levels, as well as whether or not you smoke or have a family history of type 2 diabetes. The calculator then estimates your overall risk of having a heart attack or stroke over the next decade. The ideal is a 10-year risk that’s less than 7.5 percent.

For the new study, researchers focused on the ACC/AHA calculator, which is the most commonly used. The researchers gathered health information from the medical records of more than 26,000 adults ages 40 to 79 and assessed their heart disease risks—comparing the results of the new calculator with those of the ACC/AHA calculator.

They found that the ACC/AHA calculator may have mistakenly overestimated the study subjects' risks of heart disease on average by about 20 percent. Using the new calculator would “translate into almost 12 million fewer Americans taking medications like statins,” says Nancy Cook, Sc.D., a biostatistician and professor in the department of medicine at the Brigham & Women’s Hospital and Harvard Medical School.

The study also found both underestimation and overestimation of risk for African-American adults. In about one in three, “their risk was calculated as much lower or much higher than white adults with the exact same identical risk factors,” explains Sanjay Basu, M.D., Ph.D., assistant professor of medicine at Stanford University and senior author of the new study.

That didn’t completely surprise Basu. “A couple of years ago, I had an African-American male patient in my office whom I was worried about, because I thought he had a high risk of stroke—he had high cholesterol and was a heavy smoker,” says Basu. “But when I plugged his numbers into the ACC/AHA risk calculator, his risk came up as 4 percent, which I thought seemed bizarrely low. When on a hunch I switched his ethnicity from black to white, his risk shot up to 15 percent. It made me suspect that something was off about the statistical analysis of the calculator.”

What Should You Do?

If you are African-American, it's especially important to be aware of heart disease risk factors, such as high cholesterol and high blood pressure levels or being overweight. It's also key to work to control them and to talk to your doctor about whether medication is appropriate—even if your score on a heart risk calculator is low, DeFilippis says. The same may hold true if you are Hispanic. 

No matter what ethnic group you're in, if you’re currently taking blood pressure or cholesterol medication, or daily low-dose aspirin to reduce your risk of heart attack or stroke, it’s important to have a conversation with your doctor, says Michael Hochman, M.D., M.P.H., director of the Gehr Center for Health Systems Science at the Keck School of Medicine at USC in Los Angeles. In cases like the following, there’s solid evidence for medication use:
• Uncontrolled blood pressure of 140/90 or higher if you’re under age 60, or if you’re over 60, a top number higher than 150.
• A previous heart attack or stroke. Anyone who has had such an event should automatically be put on a statin medication and daily aspirin, Hochman says.

If you don’t fit into the categories above, your doctor can use a risk assessment tool to help gauge whether you should be taking medication or not. But which one? 

You might consider the calculator developed by Basu and his team, but keep in mind that more research is needed to make sure it works for everyone, DeFilippis stresses.

Or ask your doctor about an older calculator called the Reynolds Risk Score, advises Steven Nissen, M.D., chairman of the department of cardiovascular medicine at the Cleveland Clinic.

A study published in 2015 in the Annals of Internal Medicine found that it was the least flawed of the risk calculators then available, although it did overestimate risk among men by 9 percent and underestimated it among women by 21 percent. And be aware that the Reynolds calculator was studied only in doctors and nurses, who are more likely to be at low risk than more diverse workplace groups, Basu says.

Remember, too, that a heart disease risk calculator is just a starting point for a discussion with your doctor about your overall health and the pros and cons of medication use for you. “We don’t want anyone to base treatment choices solely off of the risk calculator,” Basu says. 

For those at somewhat lower risk of heart disease—a calculator score between 7.5 and 10—trying lifestyle changes first may be worthwhile, Hochman says. That means stopping smoking, losing excess weight, being physically active, consuming a heart-healthy diet, and drinking alcohol in moderation only, which are smart strategies whether you're at risk for heart disease or not.

A combination of reduced sodium intake and the DASH diet (rich in fruits, vegetables, whole grains, low or fat-free dairy, fish, poultry, beans, seeds, and nuts), for example, appeared to dramatically lower blood pressure in adults with hypertension, according to a Beth Israel Deaconess Medical Center study presented last year at the American Heart Association Scientific Sessions’ annual meeting. If that doesn’t lower your risk enough after three to six months, then consider medication.

But at the end of the day, “the determination of whether to go on medication should be a personalized decision,” Basu says.