Does comorbidity account for the excess mortality in patients with major bleeding in acute myocardial infarction?

Analyses from randomized controlled trials suggest that bleeding in patients with acute myocardial infarction is associated with poor outcomes. Because these data are not generalizable to all patients with acute myocardial infarction, we sought to better understand the scope of this problem in a "real-world" setting.

We examined the frequency of major bleeding in 40,087 patients with acute myocardial infarction enrolled in the Global Registry of Acute Coronary Events. Regression analyses were used to examine the association between patient and treatment characteristics, bleeding, and hospital and postdischarge outcomes. Major bleeding occurred in 2.8% of patients. These patients were older, more severely ill, and more likely to undergo invasive procedures. Patients with bleeding were more likely to die during hospitalization (hazard ratio, 1.9; 95% confidence interval, 1.6 to 2.2) but not after discharge (hazard ratio, 0.8; 95% confidence interval, 0.6 to 1.0) than patients who did not bleed. Continuation of antithrombotic therapies after day 1 was lower in patients who experienced early bleeding. Moreover, in patients who bled, hospital mortality was increased in those who discontinued aspirin, thienopyridines, or low-molecular-weight heparins.

Major bleeding occurred in 1 in 35 patients with acute myocardial infarction; these patients accounted for approximately 10% of all hospital deaths. Nevertheless, risk of hospital mortality associated with bleeding was much lower than reported in randomized controlled trials. These data suggest that although bleeding may be causally related to adverse outcomes in some patients in the real-world setting, it is often merely a marker for patients at higher risk for adverse outcomes.