ASA dosing, risks and benefits

We know that increasing the dose of ASA increases the risk of major and minor bleeding (abstract), but it is unclear if the efficacy also increases with increasing dose. This was a retrospective analysis of a larger study (BRAVO trial) which enrolled patients with a recent vascular event (MI, USA, TIA, or CVA) or dual bed vascular disease, and randomized them to an oral IIb/IIIa inhibitor or placebo. In this retrospective review, researchers evaluated the ASA dose (<162 or >162mg) in those 4590 patients that recieved a placebo in the inital trial. They found all cause mortality significantly lower in the higher dose ASA group at 1 year (2.9% in those <162mg and 1.6% in those >162mg, p=.003), and also found higher overall bleeding risk (but no significant difference in major bleeding). This suggests that ASA dose >162mg is more efficacious than <162mg in preventing death in those with a recent event or signficant vascular disease, at the expense of minor (but not major) bleeding (citation: Aronow DH et al; Am J Card 2008;102(10):1285)

Danielle Scheurer

Dr. Scheurer is a clinical hospitalist and the Medical Director of Quality and Safety at the Medical University of South Carolina in Charleston, South Carolina, and is Assistant Professor of Medicine. She is a graduate of the University of Tennessee College of Medicine, completed her residency at Duke University, and completed her Masters in Clinical Research at the Medical University of South Carolina. She also serves as the Web Editor and Physician Advisor for the Society of Hospital Medicine.

1 Comment

  1. Ajith Purush, MD on November 20, 2008 at 5:05 pm

    Eliciting history of asthma or airway disease prior to giving aspirin is important. Also there is the question of aspirin insensitivity which was originally stated ti be as high as 30% but a new italian study puts it at 5%. comments.

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