Net Clinical Benefit of Dabigatran Over Warfarin in Patients With Atrial Fibrillation Stratified by CHA2DS2-VASc and Time in Therapeutic Range

Abstract

Background: Although dabigatran is 1 of the preferred agents for stroke prevention in atrial fibrillation, warfarin remains the mainstay treatment in many publicly financed health care systems. Little is known about the net clinical benefit of switching patients who are receiving warfarin and have different risk profiles and time in therapeutic range (TTR) to dabigatran. In this study, we aimed to investigate the net clinical benefit of switching warfarin to dabigatran in relation to CHA₂DS₂-VASc and TTR.

Methods: This was a hospital-based observational registry.

Results: A total of 2153 patients (72.7 ± 12.2 years; CHA₂DS₂-VASc, 3.65 ± 1.94) were included in the analysis: 1686 patients were receiving warfarin, and 467 were receiving dabigatran. After a 4.2-year follow-up, the incidence of ischemic stroke among patients receiving warfarin and dabigatran were 4.25%/y and 1.89%/y, respectively. Among patients receiving warfarin, ischemic stroke risk was positively correlated with CHA₂DS₂-VASc score and negatively correlated with TTR. It was found on regression analysis that for every 10% increase in TTR, the incidence of annual ischemic stroke decreased by 0.74%/y (R² = 0.77; P = 0.04). Patients with higher CHA₂DS₂-VASc scores had greater ischemic stroke risk reductions per 10% TTR increment (ie, for CHA₂DS₂-VASc score ≤ 2, 3-4, and ≥ 5, the reductions were -0.38%/y, -0.60%/y, and -0.84%/y, respectively). Similar trends were also observed in intracranial hemorrhage. The net clinical benefit favoured switching from warfarin to dabigatran for all patients, but the best benefit was found in those with high CHA₂DS₂-VASc and poor TTR.

Conclusions: The combination of CHA₂DS₂-VASc and TTR facilitates patient prioritization for dabigatran. The best net clinical benefit for switching from warfarin to dabigatran was found in those with both high CHA₂DS₂-VASc and poor TTR.