BACKGROUND: Little is known about the comparative effectiveness and safety of non–vitamin K antagonist oral anticoagulants (NOAC) compared to warfarin in Chinese atrial fibrillation (AF) patients. Our aim was to compare the ischemic stroke risk reduction and incidence of intracranial hemorrhage (ICH) of warfarin in relation to quality of anticoagulation control (as reflected by time in therapeutic range [TTR]), and to dabigatran and rivaroxaban in a real-world cohort of Chinese AF patients.
HYPOTHESIS: Sample size and number of combined events observed were relatively small. Residual confounding could not be ruled out.
METHODS: Of 2099 patients studied (73.1 ± 12.3 years, female: 44.6%, CHA2DS2-VASc 3.7 ± 1.9 and HAS-BLED 2.0 ± 1.0) with nonvalvular AF, 963 patients (45.9%) were on warfarin (only 16.3% had TTR ≥65%), 669 patients were on rivaroxaban, and 467 patients were on dabigatran.
RESULTS: After a mean follow-up of 21.7 ± 13.4 months, there were 156 ischemic strokes (annual incidence of 4.10%/year), with the incidence of ischemic stroke being highest in patients on warfarin with TTR <65% (5.24%/year), followed by those on rivaroxaban (3.74%/year), and those on warfarin with TTR ≥65% (3.35%/year), whereas patients on dabigatran had the lowest incidence of ischemic stroke (1.89%/year). The incidence of ICH was lowest in patients on dabigatran (0.39%/year) compared with those on rivaroxaban (0.52%/year) and warfarin, with TTR <65% (0.95%/year) and TTR ≥65% (0.58%/year). Patients on rivaroxaban 20 mg daily had similar ischemic stroke risk (1.93%/year) and ICH risk (0.21%/year) compared to dabigatran.
CONCLUSIONS: In Chinese AF patients, the benefits of warfarin therapy for stroke prevention and ICH reduction depend on TTR. Of the treatments compared, dabigatran, as well as rivaroxaban 20 mg daily, was associated with lowest ischemic stroke and ICH rates.