1. The analysis of data from more than 50,000 patients showed that both dabigatran and warfarin were associated with similar amounts of bleeding and rates of ischemic stroke.
2. Dabigatran is a safe alternative to warfarin for reducing the risk of stroke in patients with atrial fibrillation.
Evidence Rating Level: 2 (Good)
Study Rundown: The risk of ischemic stroke is elevated in patients with atrial fibrillation. One of the common methods of treated atrial fibrillation is warfarin, a vitamin K antagonist. Warfarin has been shown to have excellent efficacy; however, it requires constant monitoring to ensure that there is an international normalized ratio of 2.0 to 3.0 in all patients using this medication. Dabigatran, an oral direct thrombin inhibitor, is another, newer medication approved by the U.S. Food and Drug Administration (FDA) in 2010 for patients with nonvalvular atrial fibrillation. Unlike warfarin, dabigatran requires less monitoring and has been associated with lower rates of stroke in trials of atrial fibrillation. However, since large-scale studies are limited, the authors of this study aimed to assess the incidence of stroke, bleeding, and myocardial infarction in patients receiving dabigatran compared to Warfarin.
This study has several limitations. First, the study had limited information on outpatient international normalized ratios for warfarin-treated patients. As a result, the authors had difficulty characterizing longitudinal exposure accurately and to characterize the quality of anticoagulation. Furthermore, these results are not applicable to uninsured patients.
Relevant Reading: Effects of Dabigatran according to age in atrial fibrillation
In-Depth [retrospective cohort]: In this retrospective cohort, ischemic stroke, intracranial hemorrhage, extracranial bleeding, and myocardial infarction were identified from hospital claims for atrial fibrillation patients treated with either dabigatran or warfarin therapy. The authors observed that rates of ischemic stroke did not differ significantly between patients with dabigatran and warfarin therapy (0.80 vs. 0.94 events per 100 person-years; hazard ratio [HR], 0.92 [95% CI, 0.65 to 1.28]). Additionally, dabigatran patients were less likely to have intracranial bleeding (0.39 vs. 0.77 events per 100 person-years; HR, 0.51 [CI, 0.33 to 0.79]), but more likely to have a myocardial infarction (0.77 vs. 0.43 events per 100 person-years; HR, 1.88 [CI, 1.22 to 2.90]). In general, the results of this study are similar to other trials. Further studies must be conducted to investigate the relationship between Dabigatran and increased risk of myocardial infarction.
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