Stroke prevention using dabigatran in elderly Chinese patients with atrial fibrillation

BACKGROUND Little is known about the clinical benefit of a nonvitamin K antagonist oral anticoagulant compared with warfarin in elderly Chinese patients with atrial fibrillation (AF). OBJECTIVE The purpose of this study was to evaluate the clinical benefit of dabigatran in elderly (age >= 80 years) Chinese patients with nonvalvular AF with regard to the risk of ischemic stroke and intracranial hemorrhage (ICH). METHODS This was an observational study. RESULTS We studied 571 Chinese patients (mean age 84.8 +/- 4.0 years; 58.1% women) with nonvalvular AF. The primary outcome was hospital admission for ischemic stroke, and the secondary outcome was admission for ICH. The mean CHA(2)DS(2)-VASc (congestive heart failure [1 point], hypertension [1 point], age 65-74 years [1 point] and age >= 75 years [2 points], diabetes mellitus [1 point], prior stroke or transient ischemic attack [2 points], vascular disease [1 point], sex category [female] [1 point]) and HAS-BLED (hypertension [1 point], abnormal renal/liver function [1 point], stroke [1 point], bleeding history [1 point] or predisposition [1 point], labile international normalized ratio [1 point], elderly [age > 65 years] [1 point], drugs/alcohol concomitantly [1 point]) scores were 4.8 +/- 1.6 and 2.4 +/- 0.8, respectively. Of 571 patients, 129 (22.6%) were taking dabigatran 110 mg twice daily and the remaining were on warfarin. After a mean follow-up of 2.6 years (a total of 1471 patient-years), ischemic stroke occurred in 83 patients on warfarin (6.9% per year) compared with 4 patients on dabigatran (1.4% per year) (hazard ratio 0.22; 95% confidence interval 0.23-0.67). There were 8 incidences of ICH: 7 in patients on warfarin (0.59% per year) and 1 patient on dabigatran (0.35% per year). Dabigatran was associated with a substantially lower ischemic stroke risk (1.4% per year vs 5.4% per year) and similar ICH risk (0.35% per year vs 0.36% per year) as compared with warfarin with time in therapeutic range (TTR) >= 55%. CONCLUSION In elderly Chinese patients with AF, this study suggested that dabigatran achieved superior stroke risk reduction and similar risk of ICH compared with warfarin with TTR >= 55%. Dabigatran may be preferable to warfarin in elderly patients with AF for stroke prevention, particularly in those with poor TTR.