Safety and efficacy of dabigatran and other NOACs compared with warfarin in patients with atrial fibrillation – results of a large long-term prospective study
Anticoagulant therapy is key in the prevention of strokes in patients with atrial fibrillation. Until the introduction of new oral anticoagulants (NOACs), warfarin was the first-choice drug for these patients, but unlike NOACs, it requires careful dose titration and effect monitoring. The safety and benefits of using various anticoagulants were examined in the study below.
Patient Population
Data was collected using two American healthcare databases (MarketScan and Optum). The prospective study consisted of a total of 221,228 patients who:
- were over 18 years old;
- had a confirmed diagnosis of atrial fibrillation;
- were at risk of developing a stroke (CHA2DS2-VASc score ≥ 1);
- started anticoagulant therapy from October 2010 to September 2015;
- were on anticoagulant therapy for at least 12 months;
- did not stay in a nursing home or similar facility during the observation period (as precise data on medication use was missing in these settings).
Of the total number of patients, 102,204 were on warfarin therapy, 35,124 were taking dabigatran, 55,059 were treated with rivaroxaban, and 28,841 were on apixaban. Edoxaban therapy was not included in this study due to its market release date.
Analysis Methodology
From the patients treated with NOACs, those with comparable baseline characteristics to the warfarin-treated group were selected for final analysis using the propensity score matching method. Hospitalizations for stroke, development of life-threatening bleeding, and thromboembolic events were monitored for each included patient over 12 months of anticoagulant treatment. Additionally, other related factors that might influence the choice of suitable anticoagulant were determined in the patient cohort (e.g., comorbidities, other medications, previous hospitalizations, etc.). After analyzing data from both databases, the results regarding the safety and efficacy of warfarin and NOACs therapy, i.e., dabigatran, rivaroxaban, or apixaban, were compared.
Results
The safety and efficacy of each new oral anticoagulant were compared with warfarin. The hazard ratio (HR) for the incidence of stroke was found to be 0.75 (95% confidence interval [CI] 0.58–0.98) for dabigatran, 0.77 (95% CI 0.61–0.98) for rivaroxaban, and 0.69 (95% CI 0.50–0.96) for apixaban. The hazard ratio for the development of life-threatening bleeding was 0.72 (95% CI 0.65–0.80) for dabigatran, 0.56 (95% CI 0.49–0.64) for apixaban, and 1.02 (95% CI 0.94–1.12) for rivaroxaban.
Conclusion
The results of long-term monitoring indicated a lower risk of stroke and a lower risk of bleeding complications with dabigatran compared to warfarin. They further suggest greater efficacy of rivaroxaban in terms of stroke incidence, but the risk of serious bleeding is comparable to warfarin. When comparing apixaban with warfarin, a lower risk of bleeding complications was found with apixaban use.
Therefore, the study demonstrated an overall lower risk of stroke in patients with atrial fibrillation using new oral anticoagulants. Furthermore, a lower risk of life-threatening bleeding was found in patients taking dabigatran and apixaban. These findings are consistent with clinical trial findings.
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Source: Huybrechts K. F., Gopalakrishnan C., Bartels D. B. et al. Safety and effectiveness of dabigatran and other direct oral anticoagulants compared with warfarin in patients with atrial fibrillation. Clin Pharmacol Ther 2020 Jun; 107 (6): 1405−1419, doi: 10.1002/cpt.1753.
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