Evidence Summary

What is an Evidence Summary?

Key messages from scientific research that's ready to be acted on

Got It, Hide this
  • Rating:

For people with atrial fibrillation, new “blood thinners” (factor Xa inhibitors) reduce strokes and clots more than warfarin

Bruins Slot KMH, Berge E. Factor Xa inhibitors versus vitamin K antagonists for preventing cerebral or systemic embolism in patients with atrial fibrillation. Cochrane Database Syst Rev. 2013;8:CD008980.

Review question

How effective and safe are factor Xa inhibitors for the prevention of cerebral embolism (strokes) or systemic embolic events in people with atrial fibrillation?


Atrial fibrillation is a common type of irregular heartbeat. It can lead to small clots forming in the heart. Clots can then flow from the heart to block an artery in the brain (cerebral embolism causing a stroke) or other organ (systemic embolism of the heart—causing a heart attack—or the legs—causing gangrene).

Management of atrial fibrillation aims at reducing symptoms and preventing blood clotting. An adverse effect of preventing clots is abnormal bleeding.

For decades, anticoagulant treatment with vitamin K antagonists such as warfarin (Coumadin) has been the therapy of choice for most people with atrial fibrillation.

Factor Xa inhibitors—a new class of anticoagulants—seem to have some advantages over vitamin K antagonists.

How the review was done

This summary is based on a systematic review of 10 randomized controlled trials directly comparing warfarin with factor Xa inhibitors. Publication period was 2008 to 2013.

Studies involved 42,084 people. Age ranged from 18 to 75 years. At least 50% of participants were followed up for between 12 weeks and 1.9 years

Factor Xa inhibitors assessed were apixaban, betrixaban, darexaban, edoxaban, idraparinux, and rivaroxaban.

Outcomes included strokes, embolism in other organs, major bleeding, intracranial hemorrhage, and death from all causes.

What the researchers found

Compared with warfarin, factor Xa inhibitors

  • reduced the number of strokes and systemic embolic events by 22% (7 fewer events per 1,000 people treated).
  • reduced the number of strokes by 26% (7 fewer events per 1,000 people treated).
  • reduced the number of major bleeds by 15% (7 fewer events per 1,000 people treated). This evidence is less strong due to variation of effect across trials.
  • reduced the number of intracranial hemorrhages by 45% (6 fewer events per 1,000 people treated).
  • reduced the number of deaths from any cause by 18% (6 fewer events per 1,000 people treated).


For people with atrial fibrillation, anticoagulant treatment with factor Xa inhibitors reduces strokes and systemic embolic events compared with warfarin and also reduces the risk of bleeding.


Medications that suppress, delay, or prevent blood clots. Anticoagulants (also referred to as "blood thinners") are used to treat circulatory blockages.
Intracranial hemorrhage
Bleeding inside the skull.
Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Systematic review
A comprehensive evaluation of the available research evidence on a particular topic.

Related Web Resources

  • Coronary artery disease risk screening

    Health Link B.C.
    Men over 40 and women past menopause or over 50 should get screened for coronary artery disease (CAD) every 1 to 3 years. Your risk is higher if you have diabetes, high blood pressure, abdominal obesity, kidney disease, family history of CAD or if you smoke.
  • High cholesterol: Does reducing the amount of fat in your diet help?

    Informed Health Online
    Eat less saturated fats in your diet to help prevent heart disease. Eat less meat, butter, cheese and cream to improve your health long-term.
  • Statins: Should I Take Them to Prevent a Heart Attack or Stroke?

    This patient decision aid helps people considering taking medicines called statins to lower their risk of heart attack and stroke by comparing the benefits, risks, and side effects of both options. It also includes alternative treatment options to taking statins such as trying to lower risk with lifestyle changes.
DISCLAIMER These summaries are provided for informational purposes only. They are not a substitute for advice from your own health care professional. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the McMaster Optimal Aging Portal (

Register for free access to all Professional content