Schaefer JK, et al. - Researchers assessed the frequency and outcomes of patients adding aspirin (acetylsalicylic acid) to warfarin without a clear therapeutic indication for combination treatment. In this registry-based cohort study, 37.5% of participants took warfarin and aspirin in combination treatment without any clear aspirin therapeutic indication. At 1 year, patients on the combination therapy vs those on warfarin monotherapy had higher rates of overall bleeding, major bleeding, emergency department visits for bleeding, and hospitalizations for bleeding. The receipt of combination warfarin and aspirin therapy was associated with increased bleeding and similar observed thrombosis rates vs warfarin monotherapy.