0303-News-Afib guidelines_v2_BlogDoctors would prescribe blood thinners to nearly a million more patients if they strictly followed the latest guidelines for treating atrial fibrillation, according to a new registry analysis.

That means practically every woman and every person age 65 and older with the irregular heartbeat called atrial fibrillation, or AFib — which affects about 2.7 million Americans — would qualify for blood-thinning drugs.

Researchers expected to see an increase in the number of AFib patients recommended for anticoagulant therapy.

“But when I looked at the data and saw that it was a near-universal indication for women and for people 65 and older, I did find that surprising,” said Emily O’Brien, Ph.D., of Duke Clinical Research Institute, who led the study, published Monday in JAMA Internal Medicine.

Being female and having a history of vascular disease were added as stroke risk factors to the current guidelines, issued in 2014 by the American Heart Association, American College of Cardiology and Heart Rhythm Society. Plus, the updated stroke risk assessment tool can be used starting at age 65, a decade younger than the previous tool. Other risk factors taken into account include prior congestive heart failure, high blood pressure, diabetes and prior stroke.

Duke researchers analyzed data from a registry called ORBIT that included more than 10,000 AFib patients nationwide. They found that 988,500 more patients overall would be treated with a blood thinner under the 2014 AFib guidelines than under the 2011 guidelines.

For women, about three out of four would have been candidates for treatment under the old guidelines. Nearly all of them — 98 percent — would be deemed eligible under the 2014 recommendations. A similar jump was seen in patients 65 and older.

The findings magnify the need for future studies to now determine how closely doctors are actually following the year-old recommendations and, in addition, whether more prescriptions end up resulting in fewer blood clots, strokes and other complications from AFib, said O’Brien.

About one in five strokes occur in people with AFib, according to the AHA. While blood thinners can protect AFib patients, they also increase the risk for bleeding.

Yet newer blood thinners that have come into the market in recent years are safer than older medicines, said Ralph Sacco, M.D., a past president of the AHA who helped write the 2014 guidelines.

“In the past, too many people with atrial fibrillation were not treated appropriately with anticoagulants because of the concern about bleeding,” said Sacco, chairman of neurology at the University of Miami Miller School of Medicine. “Because of positive studies with the newer drugs, the recommendations advocate for broader use to prevent stroke.”

O’Brien said AFib patients can be assured the new guidelines are backed by the latest scientific evidence and yet they also advise doctors to consider more than just the data.

“The stroke risk estimation is only one part of the treatment equation,” O’Brien said. “The patient’s goals and preferences for avoiding stroke or avoiding bleeding are also really important parts of what should be a shared decision.”

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