A new study has found that the calculators for heart disease and stroke that doctors currently use may significantly overestimate or underestimate some people’s risk. (iStock)

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Millions of Americans may want to talk to their doctors about whether 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 calculators for heart disease and stroke that doctors currently use may significantly overestimate or underestimate some people’s 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 one 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, and they suggest that it may be more accurate.

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: You or your doctor enter information online, such as your age, gender, blood pressure and cholesterol levels, as well as whether 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 while also 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, 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 1 in 3 such people, “their risk was calculated as much lower or much higher than white adults with the exact same risk factors,” explains Sanjay Basu, an assistant professor of medicine at Stanford University and senior author of the new study.

What should you do?

If you are African American, it’s especially important to be aware of heart disease risk factors. 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, says Andrew DeFilippis, an assistant professor in the department of medicine at the University of Louisville. The same may hold true if you are Hispanic.

No matter which 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, director of the Gehr Center for Health Systems Science at the Keck School of Medicine at the University of Southern California in Los Angeles.

There’s generally a solid case for medication if:

You have uncontrolled blood pressure of 140/90 or higher if you’re younger than 60, or if you’re older, having a top number higher than 150.

You’ve previously had a 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 either of those categories, your doctor can use a risk assessment tool to help gauge whether you should be taking medication.

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, 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.

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.

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 fruit, 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 recent Beth Israel Deaconess Medical Center study. If that doesn’t lower your risk enough after three to six months, then consider medication.

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

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