Increased Use of Anticoagulants Tied to Fewer Strokes in Patients With Afib

By Lisa Rapaport

(Reuters Health) - More patients with atrial fibrillation are taking anticoagulants these days, and they're having fewer strokes as a result, a Swedish study suggests.

For the new study, researchers studied two groups of patients with atrial fibrillation to see how often they had strokes and whether they took warfarin or one of the newer oral anticoagulants (NOACs).

Researchers assessed the first group of about 41,000 patients in 2012, before warfarin alternatives were widely used, and found 52% of them warfarin. This group had an annual stroke rate of 2.1 for every 100,000 patients.

Then, researchers assessed a second group of more than 49,000 patients in 2017, after NOACs were widely available. In this group, 74% took anticoagulants, and the annual stroke rate was 1.17 for every 100,000 patients.

"The introduction of NOACs has provided more alternatives for stroke prevention in atrial fibrillation," said lead study author Dr. Tomas Forslund of the Karolinska Institutet in Stockholm.

"An increased use of NOAC or warfarin in an entire real-world atrial fibrillation population comprised of many old, frail and other high risk patients ... was associated with a decreased risk for stroke without increasing the risk for severe (bleeding)," Forslund said by email.

Even as use of blood thinners increased during the study period, bleeding didn't become more common, even among people at especially high risk for bleeding, the study found.

That may be at least in part because more people took NOACs instead of warfarin as time went on, researchers concluded in their report, online August 28 in Stroke.

The study wasn't a controlled experiment designed to prove whether or how one type of anti-clotting drug might be better at stroke prevention than another.

It's also possible that changes in other aspects of stroke prevention beyond just medication might have contributed to the decline in strokes among atrial fibrillation patients, said Tom Marshall, a researcher at the University of Birmingham in the U.K. who wasn't involved in the study.

"Increased use of any anticoagulants will reduce incidence of stroke," Marshall said by email. "NOACs may have some modest advantages over warfarin, but NOACs have mainly contributed to the recent increase largely because pharmaceutical companies have a strong incentive to educate physicians about the need to prescribe anticoagulants and to promote the use of NOACs and this chimes with the desire of physicians to prevent strokes."

Drug companies have an incentive to promote the newer drugs, becomes they command premium prices compared to older generic medicines like warfarin, Marshall noted.

Patients may also prefer NOACs and stick with this treatment more than they did with warfarin, said Dr. Wesley O'Neal, a researcher at Emory University School of Medicine in Atlanta who wasn't involved in the study.

"NOACs have fewer drug interactions, less dietary restrictions, and more favorable bleeding profiles compared with warfarin," O'Neal said by email. "The reduced risk of stroke observed in this study was directly related to the higher proportion of patients who used antithrombotic agents, and the higher rate of antithrombotic agent use occurred with the introduction of NOACs as an option for patients with atrial fibrillation."

SOURCE: https://bit.ly/2ONNl1v

Stroke 2018.

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