Abstract 8844: 10-Year Mortality is Very High, and Warfarin Use Very Low, in Patients with Myocardial Infarction and Atrial Fibrillation

Abstract

Background: Patients hospitalized for myocardial infarction (MI) who have atrial fibrillation (AF) are recommended to use warfarin for stroke prophylaxis if CHADS 2 score ≥ 2. The long-term use of warfarin in these patients and associated outcomes are not well known. Herein, we describe the use of warfarin out to one year after hospitalization and identify predictors of 10-year mortality in this population. Methods: Patients with acute MI (STEMI and NSTEMI) and AF during hospitalization undergoing cardiac catheterization between January 1, 2005 and December 31, 2007 were identified from the Duke Databank for Cardiovascular Disease. Anti-thrombotic medication use at 6 months and 1 year was assessed by mailed and telephone surveys. Multivariable Cox proportional hazards modeling was used to identify predictors of 10-year mortality. Results: A total of 882 patients were identified with a median age of 72 years (64, 79). The use of warfarin was low at discharge (24%), and increased only slightly at 6 months (26%), and one year (27%), despite decreasing clopidogrel use and stable aspirin use over that time ( Figure 1 ). With a higher CHADS 2 score, warfarin use increased (CHADS 2 0, 18%; CHADS 2 1, 21%; CHADS 2 ≥2, 27%; p=0.06). In general, patients who received warfarin at discharge had similar baseline characteristics compared with those who did not. The 10-year mortality rate in this study was high and similar regardless of whether warfarin was (71.0%) or was not (70.7%) used at discharge (p=0.12). The strongest predictors of 10-year mortality in this population were: older age (HR 1.44 per 10 year, 95% CI 1.31-1.59), history of heart failure (HR 1.63, 95% CI 1.35-1.97), and higher Charlson comorbidity index (HR 1.19, 95% CI 1.11-1.27). Conclusions: Patients with MI and AF have high 10-year mortality. The use of warfarin was low, even among patients with high CHADS 2 score, remained low out to one year after discharge, and is not explained by the use of alternative antithrombotic regimens.