Balancing the Benefits and Risks of Two Doses of Dabigatran Compared With Warfarin in Atrial Fibrillation
What is the net clinical benefit of dabigatran 110 mg bid and 150 mg bid with that of warfarin in patients with atrial fibrillation (AF)?
In 18,113 AF patients in the RE-LY trial, the investigators used a previously developed method for integrating ischemic and bleeding events as “ischemic stroke equivalents” in order to compare a weighted benefit of two doses of dabigatran with each other, and with that of warfarin. The authors first calculated the crude incidence rate (IR) per 100 patient-years for the first occurrence of each outcome for patients receiving dabigatran 110 mg bid, dabigatran 150 mg bid, and warfarin. Net clinical benefit was defined as the weighted sum of these rates in the experimental group minus the weighted sum of these rates in the comparator group.
Compared with warfarin, there was a significant decrease in ischemic stroke equivalents with both dabigatran doses: -0.92 per 100 patient-years (95% confidence interval [CI], -1.74 to -0.21; p = 0.02) with dabigatran 110 mg bid, and -1.08 (95% CI, -1.86 to -0.34; p = 0.01) with dabigatran 150 mg bid. There was no significant difference in ischemic stroke equivalents between the two doses: -0.16 (95% CI, -0.80 to 0.43) comparing dabigatran 150 mg bid with 110 mg bid. When including death in the weighted benefit calculations, the results were similar.
The authors concluded that both doses of dabigatran as compared with warfarin have similar benefits when considering a weighted estimate including both efficacy and safety.
This study reported that both dabigatran 110 mg bid and dabigatran 150 mg bid were superior to warfarin when considering their integrated effects on major ischemic and bleeding events. At a group level, each dabigatran dose prevents about one more ischemic stroke equivalent (compared with warfarin) for every 100 patients treated for a year. Overall, these data suggest that the best balance between benefit and risk for individual patients may be obtained by tailoring the dabigatran dose according to a patient’s risk of stroke and bleeding.
Keywords: Stroke, beta-Alanine, Benzimidazoles, Warfarin, Confidence Intervals, Risk Assessment, Hemorrhage
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