Chest
ReviewsWarfarin Anticoagulation and Outcomes in Patients With Atrial Fibrillation: A Systematic Review and Metaanalysis
Section snippets
Materials and Methods
In general, procedures for this review followed established best methods for the evolving science of systematic review research.1112 A protocol was written prospectively, which stated the objectives, search criteria, study selection criteria, data elements of interest, and plans for analysis.
Studies
Seven hundred forty-one abstracts were screened, and 211 full articles were retrieved. Of these, 21 primary (and 9 linked) studies5678914151617181920212223242526272829303132333435363738 met our inclusion criteria and were accepted for this review. Most of the remaining articles were rejected either because INR was not reported, or the study included a mixed population, in which outcomes for patients with AF were not separable.
Table 1presents a summary of study characteristics for the accepted
Discussion
The results are in line with the current clinical belief39 that low INR is associated with an increased risk of stroke and high INR is associated with increased risk of bleeding. The available evidence indicates a higher incidence of ischemic stroke in patients with nonvalvular AF with insufficient anticoagulation (INR < 2), and a higher incidence of bleeding events in overanticoagulated patients with nonvalvular AF (INR > 3). Further, the results of well-controlled, published clinical trials723
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Sponsored by AstraZeneca LP, Wilmington, DE.
Dr. Reynolds is an employee of MetaWorks whose company was contracted by AstraZeneca to conduct the systematic review and metaanalysis presented in this article. Other coauthors of this article have not received anything of value either directly or indirectly from a commercial or other party related directly or indirectly to the subject of this article submission.
For instructions on attaining CME credit, see page A-56 or visit www.chestnet.org
Learning Objectives: 1. To recognize that the INR below 2.0 was associated with a 5-fold increase in the risk of stroke in patients with nonvalvular atrial fibrillation. 2. To understand that an INR over 3 increased the risk of major bleeding 3-fold.