Background and purpose: The objective of the study was to assess the effectiveness of individual direct oral anticoagulants versus vitamin K antagonists for primary prevention of stroke (ischemic and hemorrhagic) in routine clinical practice in patients with various clinical risk factors depending on their atrial fibrillation (AF) patterns.
Methods: A nested case-referent study was conducted using data from 2 national registries of patients with stroke and AF. Stroke cases with previous history of AF were matched to up to 2 randomly selected referent patients with AF and no stroke. The association of individual anticoagulant use with ischemic or hemorrhagic stroke was studied in patients with or without permanent AF using multivariable conditional logistic models, controlled for clinically significant risk factors and multiple other cardiovascular risk factors.
Results: In total, 2586 stroke cases with previous AF and 4810 nonstroke referent patients with AF were retained for the study. Direct oral anticoagulant users had lower odds of stroke of any type than vitamin K antagonist users: the adjusted-matched OR for ischemic stroke were 0.70 (95% CI, 0.50–0.98) for dabigatran, 0.68 (95% CI, 0.53–0.86) for rivaroxaban, and 0.73 (95% CI, 0.52–1.02) for apixaban while for hemorrhagic stroke they were 0.31 (95% CI, 0.14–0.68), 0.64 (95% CI, 0.39–1.06), and 0.70 (95% CI, 0.33–1.49), respectively. The effects of individual direct oral anticoagulants relative to vitamin K antagonists were similar in permanent AF and nonpermanent AF patients.
Conclusions: Similar results were observed for each direct oral anticoagulant in real life as those observed in the pivotal clinical trials. The pattern of AF did not affect the outcome.
Keywords: anticoagulants; atrial fibrillation; effectiveness; stroke.