A nationwide registry study to compare bleeding rates in patients with atrial fibrillation being prescribed oral anticoagulants
Key result
Apixaban (HR 0.70; 95% CI 0.61-0.80) and dabigatran (HR 0.74; 95% CI 0.66-0.84) were associated with a lower risk of major or CRNM bleeding compared with warfarin in patients with atrial fibrillation.
Why the study?
Do direct oral anticoagulants (dabigatran, rivaroxaban, or apixaban) reduce major or clinically relevant non-major bleeding in patients with atrial fibrillation compared with warfarin?
Population
32,675 patients with atrial fibrillation with a first prescription of oral anticoagulants, 58% men, median…
Comparison
Direct oral anticoagulants vs Warfarin
Design
Cohort
Follow-up
median 173 days
Authors
Discussion
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Implication
Supports apixaban or dabigatran preference in AF; extends RCT data to real-world cohorts but leaves practice change open.
Key Points
- To evaluate and compare real-world bleeding risks among patients with atrial fibrillation prescribed dabigatran, rivaroxaban, or apixaban versus warfarin.
- Nationwide registry study in Norway linking the Norwegian Patient Registry and Norwegian Prescription Database to identify N=32,675 atrial fibrillation patients initiating oral anticoagulants between January 2013 and June 2015.
- Treatment cohorts included warfarin (n=11,427), dabigatran (n=7,925), rivaroxaban (n=6,817), and apixaban (n=6,506), followed for a median of 173 days (25th, 75th percentile: 84, 340) until drug cessation, switching, death, or study completion.
- Adjusted Cox proportional hazard models assessed the primary endpoint of first major or clinically relevant non-major (CRNM) bleeding, as well as gastrointestinal and intracranial bleeding subtypes.
- A first major or CRNM bleeding event occurred in 2,081 patients (6.37%) overall; apixaban (HR 0.70, 95% CI 0.61–0.80, P < 0.001) and dabigatran (HR 0.74, 95% CI 0.66–0.84, P < 0.001) significantly reduced bleeding risk compared to warfarin, whereas rivaroxaban did not (HR 1.05, 95% CI 0.94–1.17, P = 0.400).
- Compared with warfarin, dabigatran and rivaroxaban were associated with higher risks of gastrointestinal bleeding, while apixaban and dabigatran were associated with lower risks of intracranial bleeding.
Study Design
Type
Cohort (n=32,675)
Multicenter
Yes
Structured PICO
Do direct oral anticoagulants (dabigatran, rivaroxaban, or apixaban) reduce major or clinically relevant non-major bleeding in patients with atrial fibrillation compared with warfarin?
P
Population
32,675 patients with atrial fibrillation prescribed oral anticoagulants, followed for a median of 173 days.
E
Exposure
Direct oral anticoagulants (dabigatran, rivaroxaban, or apixaban)
C
Comparator
Warfarin
O
Outcome
Major or clinically relevant non-major (CRNM) bleedingsafety
Main Result
Hazard Ratio: 0.7 (95% CI 0.61–0.8)
p-value: p=<0.001
In real-world clinical practice, apixaban and dabigatran are associated with a lower risk of major or clinically relevant non-major bleeding compared to warfarin in patients with atrial fibrillation.
Cite This Study
Halvorsen et al. (2016) conducted a cohort in Atrial fibrillation (n=32,675). Apixaban, dabigatran, or rivaroxaban vs. Warfarin was evaluated on Major or clinically relevant non-major (CRNM) bleeding (HR 0.70, 95% CI 0.61-0.80, p=<0.001). Apixaban (HR 0.70; 95% CI 0.61-0.80) and dabigatran (HR 0.74; 95% CI 0.66-0.84) were associated with a lower risk of major or CRNM bleeding compared with warfarin in patients with atrial fibrillation.