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Effects of dabigatran according to age in atrial fibrillation
Mandy N Lauw1,2, John W Eikelboom1, Michiel Coppens1,2
1McMaster University and Hamilton Health Sciences, Population Health Research Institute, Hamilton, Ontario, Canada.
Insights
Dabigatran effectively prevents stroke and intracranial bleeding in atrial fibrillation patients across all ages compared to warfarin. However, extracranial bleeding risk varies by age, with the lower dabigatran dose recommended for older adults.
Area of Science:
- Cardiology
- Pharmacology
- Geriatrics
Background:
- Atrial fibrillation (AF) prevalence and associated risks of stroke and bleeding increase with age.
- Understanding age-specific treatment effects is crucial for optimizing anticoagulation therapy.
- The Randomized Evaluation of Long-Term Anticoagulant Therapy (RE-LY) trial provides a robust dataset for this analysis.
Purpose of the Study:
- To evaluate the age-dependent effects of dabigatran versus warfarin on stroke, bleeding, and mortality in patients with AF.
- To determine if treatment benefits and risks differ across various age groups.
Main Methods:
- Analysis of data from the RE-LY trial, including over 18,000 patients stratified by age categories (<75, 75-79, 80-84, ≥85 years).
- Comparison of dabigatran (110mg and 150mg twice daily) with warfarin, analyzing treatment effects using age as a continuous variable and in categories.
- Statistical analysis focused on interactions between age and treatment for stroke, intracranial bleeding, and extracranial major bleeding.
Main Results:
- Dabigatran demonstrated consistent benefits over warfarin for stroke prevention and intracranial bleeding across all age groups.
- A significant age-treatment interaction was observed for extracranial major bleeding (p<0.001).
- Dabigatran showed lower extracranial bleeding rates in younger patients but similar or higher rates in patients aged 80 years and older compared to warfarin.
Conclusions:
- Dabigatran offers consistent stroke prevention and intracranial bleeding protection compared to warfarin, irrespective of patient age.
- Age-specific considerations are vital for managing extracranial bleeding risk with dabigatran.
- The 110mg twice daily dose of dabigatran is supported for elderly patients (≥80 years) due to its safety profile regarding extracranial bleeding.
Objective:
The prevalence of atrial fibrillation (AF) and the risk of stroke and bleeding vary according to age. To estimate effects of dabigatran, compared with warfarin, on stroke, bleeding and mortality in patients with AF in the Randomized Evaluation of Long-Term Anticoagulant Therapy (RE-LY) trial according to age, we analysed treatment effects using age as a continuous variable and using age categories.
Methods:
RE-LY included 10 855 (59.9%) patients aged <75 years, 4231 patients (23.4%) aged 75-79 years, 2305 (12.7%) aged 80-84 years and 722 (4.0%) aged ≥85 years at baseline.
Results:
Benefits of dabigatran versus warfarin regarding stroke (HR range 0.63 (95% CI 0.46 to 0.86) to 0.70 (0.31 to 1.57) for dabigatran 150 mg twice daily), HR range 0.52 (0.21 to 1.29) to 1.08 (0.73 to 1.60) for dabigatran 110 mg twice daily) and intracranial bleeding were maintained across all age groups (interaction p values all not significant). There was a highly significant interaction (p value interaction <0.001) between age and treatment for extracranial major bleeding, with lower rates with both doses of dabigatran compared with warfarin in younger patients (HR 0.78 (0.62 to 0.97) for 150 mg twice daily, HR 0.72 (0.57 to 0.90) for 110 mg twice daily) but similar (HR 1.50 (1.03 to 2.18) for 110 mg twice daily) or higher rates (HR 1.68 (1.18 to 2.41) for 150 mg twice daily) in older patients (≥80 years).
Conclusion:
Effects of dabigatran compared with warfarin on stroke prevention and intracranial bleeding are consistent across all age groups. Effects of dabigatran on extracranial major bleeding are age dependent, supporting selection of dabigatran 110 mg twice daily for elderly patients (age ≥80 years).
Trial Registration Number:
Clinical trial registration number: https://clinicaltrials.gov NCT00262600.
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