Study Question:

What is the risk:benefit ratio of warfarin in patients with atrial fibrillation (AF)?

Methods:

The data in this study were obtained from a national database that included 170,292 patients (mean age 76 years) with a diagnosis of AF in 2005-2008. Fifty-three percent of patients were not treated with warfarin. The mean duration of follow-up was 1.5 years. Net clinical benefit (NCB) was defined as the number of ischemic strokes off warfarin minus the number of intracranial hemorrhages on warfarin with a weight of 1.5 to account for the more severe consequences of intracranial hemorrhage. NCBs were analyzed according to stroke risk (CHA₂DS₂-VASc score) and bleeding risk (HAS-BLED score).

Results:

The NCB favored warfarin for patients with a CHA₂DS₂-VASc score ≥1. The greatest NCB occurred in patients with the highest risk scores. The adjusted NCB was >6%/year in patients with a CHA₂DS₂-VASc score of 6 and a HAS-BLED score of 4. In the small subgroup of patients with a CHA₂DS₂-VASc score of 0 and moderately elevated bleeding risk, the NCB did not favor warfarin.

Conclusions:

The authors concluded that the risk of ischemic stroke off warfarin exceeds the risk of intracranial hemorrhage on warfarin for almost all patients with AF.

Perspective:

Of note is that the risk of intracranial bleeding on warfarin exceeded the risk of ischemic stroke off warfarin in only 0.4% of patients in this very large AF cohort. The data indicate that almost all patients with AF have more to gain than to lose from anticoagulation with warfarin.

Author(s):

Fred Morady, M.D., F.A.C.C. (Disclosure)

Topic(s):

Arrhythmias, Afib, Cardiac Rhythm Management, General Cardiology