Abstract 1116: Atrial Fibrillation Patients At The Highest Risk Of Thromboembolism Have The Least Knowledge Of Warfarin Use
Background: Warfarin anticoagulation has been shown to significantly reduce stroke risk in patients with atrial fibrillation (AF). Warfarin has a narrow therapeutic index with hazards of both thromboembolism and hemorrhage. Multiple factors influence warfarin metabolism and can significantly impact risk. It is unclear what modifiable factors that impact warfarin safety and efficacy patients understand.
Methods: This study was conducted to assess the understanding of an AF population and their understanding of warfarin. A 52-item questionnaire related to knowledge of warfarin was administered in a face-to-face interview with a dietitian. Results were compiled based on five categories: general warfarin knowledge, compliance, drug interactions, herbal or vitamin interactions, and diet. The data was stratified by education level, stroke risk as measured by CHADS2 score, and duration of warfarin use.
Results: 100 patients were surveyed, 62 (62%) male with an average age of 68 years. Stroke risk factors included hypertension (57%), heart failure (36%), age>75 (33%), diabetes (22%), prior stroke/TIA (29%). The majority were either a high school (49%) or college graduate (27%). Ten (10%) had a stroke on warfarin, 11 (11%) had a blood transfusion, 26 (26%) had at least one fall. The following questions regarding warfarin were answered correctly: general knowledge (62%), compliance (71%), drug interaction (17%), herbal/vitamin interaction (7%), and diet (23%). Scores were significantly higher in those with a high school education or greater. Patients at highest risk of stroke (CHADS2 score 3–5) had significantly lower scores in all categories. Duration of warfarin use did not influence assessed understanding. Forty one (41%) patients reported warfarin significantly decreased their quality of life primarily due to concern of bleeding.
Discussion: Patients on warfarin have a poor general understanding of the medication. High risk patients have the least understanding and are at significant risk of drug related adverse outcomes. Duration of warfarin use did not impact understanding suggesting the need for frequent education. These data likely explain variability in warfarin therapy efficacy and highlight the need for novel education approaches.