The Dose of Direct Oral Anticoagulants and Stroke Severity in Patients with Acute Ischemic Stroke and Nonvalvular Atrial Fibrillation

Background: The severity and the functional outcome of patients with stroke occurring during off-label underdosing of direct-acting oral anticoagulants (DOACs) remain uncertain. Methods: We studied 53 consecutive patients with acute ischemic stroke and nonvalvular atrial fibrillation who were treated with DOACs before the onset of stroke. Thirty patients were treated for primary prevention of stroke and 23 patients were treated for secondary prevention. DOAC treatments were categorized into 3 groups based on the following doses: (1) standard-dose group (n = 17), (2) low-dose group (n = 23), and (3) off-label underdose group (n = 13). Results: Age was significantly older in the low-dose group than in the standard-dose group (P = .026). The standard-dose group and the low-dose group showed higher CHA(2)DS(2)-VASc scores (median, 4) compared with the off-label underdose group (median, 3). More than half of the patients had a National Institutes of Health Stroke Scale score of less than 8, and many patients had a good outcome (modified Rankin Scale score <= 1). There were no differences in stroke severity and outcome among the 3 groups. The ratio of being discharged home was the highest in the standard-dose group. Conclusions: This study shows that patients who have off-label underdosing of DOACs do not develop more severe stroke and a poorer outcome than those with the recommended dose. Careful attention to recommended doses is required for the full benefits from DOACs.