Little is known about patients with 1 dose-reduction criterion who received the 5 mg twice daily dose of apixaban.To determine the frequency of 1 dose-reduction criterion and whether the effects of the 5 mg twice daily dose of apixaban on stroke or systemic embolism and bleeding varied among patients with 1 or no dose-reduction criteria.Among 18 201 patients in the ARISTOTLE trial, 17 322 were included in this analysis.