Warfarin use and long-term outcomes in patients with acute myocardial infarction and atrial fibrillation

Warfarin use in patients with acute myocardial infarction (AMI) and atrial fibrillation (AF) remains challenging. We describe use of warfarin up to 1 year after hospitalization among patients with AMI and AF according to stroke and bleeding risk, and identify factors associated with long-term mortality in this population. Patients with AMI and AF who underwent cardiac catheterization during their AMI hospitalization in 1995–2007 were identified from the Duke Databank for Cardiovascular Disease. Warfarin use at discharge, 6 months, and 1 year as well as long-term vital status were assessed by surveys. Rates of warfarin use were presented according to CHADS₂ and CHA₂DS₂VASc stroke and ATRIA bleeding risk scores. Cox proportional hazards modeling was used to determine whether warfarin use at discharge was independently associated with 1-year mortality. A total of 879 patients hospitalized with AMI with AF were identified. Median age was 72 (25th, 75th percentiles: 64, 79), and median follow-up was 4.1 years (1.3, 7.4). The rate of warfarin use at discharge was 24 % and did not differ by CHADS₂, CHA₂DS₂VASc, or ATRIA risk scores. Warfarin use remained similar at 6 months (26 %) and 1 year (27 %). Long-term mortality was high and did not differ by whether warfarin was or was not prescribed at discharge (72 and 71 %, respectively). Factors associated with 1-year mortality were history of heart failure (HR 1.58, 95 % CI 1.32–1.90), higher Charlson comorbidity index (HR 1.19, 95 % CI 1.11–1.28), and older age (HR 1.03 per 1-year increase, 95 % CI 1.02–1.05). Warfarin use at discharge among patients hospitalized for AMI who had comorbid AF was low and remained low at 1 year. Warfarin use at hospital discharge was not associated with either 1-year mortality or long-term mortality.