Persistence of Warfarin Therapy for Residents in Long-term Care Who Have Atrial Fibrillation

Background: Among long-term care (LTC) residents with atrial fibrillation (AF), the use of warfarin to prevent stroke has been shown to be suboptimal. For those who begin warfarin prophylaxis in LTC, persistence on this therapy has not been reported. Objective: This study was conducted to estimate persistence on warfarin among LTC residents with AF. Methods: A retrospective analysis was conducted by using data from an LTC database. Pharmacy dispensing data were used to track warfarin use in residents with a diagnosis of AF who were newly started on warfarin therapy. The main outcome measure was persistence of warfarin over the first year of therapy. Survival analysis included Kaplan-Meier plots and a multivariate Cox proportional hazards model to test the association of resident characteristics and conditions with warfarin discontinuation. Results: A total of 148 residents new to warfarin therapy met all study inclusion criteria. Median age was 84 years; 69% were female. Median time to therapy discontinuation was 197 days (95% CI, 137-249) across all study residents. By 90 days after the initiation of therapy, 37% (95% CI, 28-47) of study residents had discontinued warfarin; by 1 year, 65% (54%-76%) had discontinued warfarin therapy. The multivariate Cox regression analysis found that the following factors were independently associated with discontinuation of warfarin therapy: age 65 to 74 years (hazard ratio [HR] = 3.01 [95% CI, 1.04-8.73]), female sex (HR = 0.45 [95% CI, 0.24-0.87]), Hispanic race/ethnicity (HR = 2.86 [95% CI, 1.30-6.26]), Midwest region (HR = 2.13 [95% CI, 1.02-4.48]), and Alzheimer disease or dementia (HR = 1.97 [95% CI, 1.05-3.68]). Conclusions: Although clinical practice guidelines exist for the prevention of stroke in AF patients, persistence on warfarin therapy seems suboptimal in many LTC residents with AF. (C) 2013 Published by Elsevier HS Journals, Inc.