Atrial Fibrillation and Stroke Prevention With Warfarin in the Long-term Care Setting

Background: While the benefits of warfarin sodium therapy for stroke prevention in patients with atrial fibrillation (AF) have been extensively documented, generalizing clinical trial results to the majority of elderly persons with AF, especially to those who reside in the long-term care setting, remains challenging. Objectives: To determine the prevalence of AF in the institutionalized elderly population and the proportion receiving anticoagulation therapy with warfarin; to identify the clinical and functional characteristics of institutionalized elderly persons with AF that are associated with the use of warfarin; and to assess the quality of prescribing and monitoring of warfarin therapy in institutionalized elderly persons with AF. Methods: This study involved 30 long-term care facilities (total No. of beds, 6437) located in New England, Quebec, and Ontario. The proportion of patients with AF who were receiving treatment with warfarin was determined. The association between clinical and functional characteristics and the use of warfarin was examined with crude and multivariable-adjusted analyses. For study subjects with at least 2 weeks of warfarin therapy during the 12-month period preceding the date of medical record abstraction, we assessed the quality of warfarin prescribing based on all international normalized ratio or prothrombin time ratio values during this period. Results: An electrocardiogram indicating AF was present in the records of 413 of 5500 long-term care residents (7.5%); 32% of such patients were being treated with warfarin. Only a history of stroke was found to be positively associated with the use of warfarin in this setting. Patients with a diagnosis of dementia and those in the oldest age group (≥85 years) were less likely to receive warfarin therapy. Warfarin was commonly prescribed to patients with a history of bleeding, substantial comorbidity and functional impairment, a history of falls, or concomitant potentiating drug therapy. Patients were maintained above or below the recommended therapeutic range 60% of the time. Conclusions: Atrial fibrillation is common in patients residing in long-term care facilities, but its management with warfarin is highly variable. A more systematic approach to decision making regarding the use of warfarin for stroke prevention in these patients is required. Among patients receiving warfarin, the quality of anticoagulation care warrants improvement. Arch Intern Med. 1997;157:978-984