Abstract 12693: Patterns of Discharge Aspirin Dosing in 213,344 U.S. Patients after Acute Myocardial Infarction: Results from the NCDR

Abstract

Background: Optimal dosing of aspirin (ASA) after acute MI has been a source of controversy, as reflected by inconsistent recommendations from contemporary practice guidelines. Recent observational findings from clinical trial data suggest that low-dose ASA may offer similar efficacy to higher dose, with reduced risk of bleeding.

Methods: Using the ACTION Registry®-GWTG™, we describe contemporary discharge ASA dosing patterns in the U.S, overall and in subgroups defined by MI management strategy, concomitant medication use, and recent bleeding events. High-dose ASA was defined as 325 mg and low-dose as 81 mg.

Results: Among 213,344 acute MI patients (40.2% STEMI) from 525 U.S. hospitals enrolled between January 2007 and March 2011, 60.9% were discharged on high-dose ASA, 35.6% on low-dose ASA, and 3.3% on 162 mg. High-dose ASA was prescribed at discharge to 73.0% of patients treated with PCI and 44.6% of patients managed medically (Figure). Even among 9,075 patients discharged on “triple therapy” (aspirin, thienopyridine, and warfarin), 44.0% were prescribed high dose aspirin. Patients with an in-hospital major bleeding event were also frequently discharged on high dose aspirin (56.7%). Patterns of ASA dosing were stable in all subgroups over time.

Conclusions: Most U.S. MI patients are discharged on high dose aspirin, including almost half of those receiving “triple therapy”, and more than half of those with major bleeding. Although practice patterns in stented patients largely reflect prevailing US guidelines, ASA dosing in the US overall, and especially in medically managed patients or those on “triple therapy” stands in sharp contrast to the near exclusive use of low-dose ASA in the rest of the world.