Efficacy and Safety of Dabigatran Etexilate and Warfarin in ‘Real World’ Patients With Atrial Fibrillation: A Prospective Nationwide Cohort Study

Study Questions:

What is the safety and efficacy of anticoagulant-naïve patients with atrial fibrillation (AF) treated with dabigatran etexilate following its post-approval availability in a nationwide Danish cohort, compared to warfarin?

Methods:

This was a retrospective cohort analysis. The authors identified a dabigatran-treated group (n = 4,978) and a 1:2 propensity-matched warfarin-treated group (n = 8,936). The primary study outcomes were stroke, systemic embolism, and intracranial bleeding. Secondary outcomes were death from any cause, gastrointestinal bleeding, traumatic intracranial bleeding, or major bleeding. Comparisons on efficacy and safety outcomes were based on Cox proportional hazards models stratified on propensity match groups.

Results:

Stroke and systemic embolism were not significantly different between warfarin- and dabigatran-treated patients in the adjusted analyses. Mortality was significantly lower in the dabigatran 110 mg twice daily and dabigatran 150 mg twice daily groups compared to the warfarin-treated group (adjusted hazard ratio [HR], 0.79; 95% confidence interval [CI], 0.65-0.95 and adjusted HR, 0.57; 95% CI, 0.40-0.80, respectively). Less intracranial bleeding was seen with both dabigatran doses (110 mg twice daily, adjusted HR, 0.24; 95% CI, 0.08-0.56 and 150 mg twice daily, adjusted HR, 0.08; 95% CI, 0.01-0.40). The incidence of myocardial infarction was lower with both dabigatran doses (110 mg twice daily, adjusted HR, 0.30; 95% CI, 0.18-0.49 and 150 mg twice daily, adjusted HR, 0.40; 95% CI, 0.21-0.70).

Conclusions:

Compared to warfarin, in a post-approval Danish cohort, the efficacy of dabigatran was similar to that of warfarin. Adjusted mortality, intracranial bleeding, and myocardial infarction were lower with dabigatran, compared to warfarin.

Perspective:

In this post-approval study of dabigatran-treated patients compared against a propensity-matched group managed with warfarin, there was no evidence of an excess of bleeding events or myocardial infarction. This may dispel previous concerns about an excess of bleeding events or myocardial infarction amongst dabigatran-treated patients. Efficacy in terms of stroke and systemic embolism prevention was also similar between warfarin and dabigatran (both doses). The overall risk of the Danish population should be considered. The Danish cohort in this analysis had a mean CHADS2 score of 1.16 (compared to 2.13 in the RE-LY [Randomized Evaluation of Long-Term Anticoagulant Therapy] trial).

Clinical Topics: Anticoagulation Management, Novel Agents

Keywords: Incidence, Myocardial Infarction, Stroke, Intracranial Hemorrhages, Biological Markers, Benzimidazoles, Cardiology, Warfarin, Pyridines


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