The effect of cognitive impairment in the elderly on the initial and long-term stability of warfarin therapy.

Background: Despite guidelines that clearly outline the benefits of warfarin, it remains underutilized. Various reasons are associated with the underuse of warfarin; however, cognitive impairment (CI) has been identified as one of the most common causes for not electing to anticoagulate elderly patients with atrial fibrillation. Nevertheless, there are limited data on warfarin use in such patients; therefore, we investigated anticoagulation stability in patients with and without CI.

Warfarin maintenance dose in older patients: higher average dose and wider dose frequency distribution in patients of African ancestry than those of European ancestry.

Studies report that warfarin doses required to maintain therapeutic anticoagulation decrease with age; however, these studies almost exclusively enrolled patients of European ancestry. Consequently, universal application of dosing paradigms based on such evidence may be confounded because ethnicity also influences dose. Therefore, we determined if warfarin dose decreased with age in Americans of African ancestry, if older African and European ancestry patients required different doses, and if their daily dose frequency distributions differed.