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Nov 20, 2015

Sex Differences in Blood Thinner Treatment for AFib

Despite the drug’s benefits, women are less likely to receive optimal dose of dabigatran.

Although the blood thinner dabigatran helps atrial fibrillation (AFib) patients reduce their risk for stroke, women are less likely to receive the optimal dose compared to men, according to a study recently conducted in Quebec, Canada.

Published in the American Heart Association journal Circulation: Cardiovascular Quality and Outcomes, this study investigated dabigatran use among men and women with AFib. AFib is the most common type of irregular heart rhythm in the United States, currently affecting an estimated 2.7 million Americans. Since patients with AFib are at high risk for stroke, blood thinners are typically used to reduce risk of complications. However, women with AFib have a higher risk of stroke than men and may require different treatment to reduce cardiovascular risk.

To learn more, researchers compared use of two common blood thinners—warfarin and dabigatran. First approved in the 1950s, warfarin is one of the most widely used blood thinners in the world. Dabigatran, however, is a new type of blood thinner approved by the U.S. Food and Drug Administration in 2010. Studies suggest that dabigatran may be safer and more effective than warfarin, but little is known about treatment differences among men and women.

A total of 63,000 men and women were included in the recent study, all of whom filled prescriptions for dabigatran or warfarin between 1999 and 2013. Using medical records, researchers compared outcomes like stroke and bleeding—a known complication of blood thinners.

After analysis, researchers found that the higher dose (150 mg twice daily) of dabigatran reduced risk for stroke in women. However, women were 35% more likely to take the lower dose (110 mg twice daily) of dabigatran than men.

Data also showed that among male patients, those taking dabigatran had lower risk of bleeding than patients taking warfarin. And dabigatran did not increase risk for heart attack in either sex, despite concerns raised in past studies.

The good news is that the newer blood thinner dabigatran appears to be both safe and effective in men and women. Not only did dabigatran reduce risk for bleeding in men, it helped reduce risk for stroke in women.

However, findings suggest that most women with AFib are not receiving optimal treatment. Therefore, authors encourage future research to further investigate sex differences in blood thinner use for this condition.

Questions for You to Consider

  • What is atrial fibrillation?

  • Atrial fibrillation is an irregular heart rhythm caused by abnormal, chaotic electrical impulses in the heart’s upper chambers, the atria. These electrical impulses, which interfere with the heart’s natural pacemaker, fire so rapidly the atria cannot beat with a regular rhythm or squeeze out blood effectively. Instead, they merely quiver while the ventricles, the heart’s lower chambers, beat rapidly.
  • Does atrial fibrillation increase stroke risk?
  • Yes. Left untreated, AFib causes a five-fold increase in risk for stroke and doubles the risk of heart-related deaths. However, treatment and medication can help significantly reduce risk of complications.

Featured Video

Dr. Kanny S. Grewal, FACC, presents at a Living with Atrial Fibrillation event in Columbus, Ohio in Oct. 2014.


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