(HealthDay News) — Most U.S. patients with myocardial infarction (MI) are discharged on high-dose aspirin, according to a study published online August 12 in Circulation: Cardiovascular Quality and Outcomes.

Hurst M. Hall, MD, from the University of Texas Southwestern Medical Center in Dallas, and colleagues examined contemporary aspirin dosing patterns from 221,199 patients with MI from 525 U.S. hospitals.

The researchers found that, of the patients with acute MI, 60.9% were discharged on high-dose aspirin (325mg), 35.6% on low-dose aspirin (81mg), and 3.5% on other doses between January 2007 and March 2011. Seventy-three percent of those treated with percutaneous coronary intervention and 44.6% of those managed medically were prescribed high-dose aspirin at discharge. Forty-four percent of the 9,075 patients discharged on aspirin, thienopyridine, and warfarin were prescribed high-dose aspirin. More than half (56.7%) of patients with an in-hospital major bleeding event were also discharged on aspirin. Across participating centers there was a 25-fold variation in the proportion prescribed high-dose aspirin at discharge.

“Wide variability in the proportional use of high-dose aspirin across centers suggests significant influence from local practice habits and uncertainty about appropriate aspirin dosing,” the authors write.

Several authors disclosed financial ties to pharmaceutical companies, including Merck and Bristol-Myers Squibb, which funded the study.

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