Associations of major bleeding and myocardial infarction with the incidence and timing of mortality in patients presenting with non-ST-elevation acute coronary syndromes: a risk model from the ACUITY trial

Abstract

To evaluate the associations of myocardial infarction (MI) and major bleeding with 1-year mortality. Both MI and major bleeding predict 1-year mortality in patients presenting with acute coronary syndrome (ACS). However, the risk of each of these events on the magnitude and timing of mortality has not been well studied. A multivariable Cox regression model was developed relating 13 independent baseline predictors to 1-year mortality for 13 819 patients with moderate and high-risk ACS enrolled in the Acute Catheterization and Urgent Intervention Triage strategy trial. After adjustment for baseline predictors, Cox models with major bleeding and recurrent MI as time-updated covariates estimated the effect of these events on mortality hazard over time. Within 30 days of randomization, 705 patients (5.1%) had an MI, 645 (4.7%) had a major bleed; 524 (3.8%) died within a year. The occurrence of an MI was associated with a hazard ratio of 3.1 compared with patients not yet having an MI, after adjustment for baseline predictors. However, MI within 30 days markedly increased the mortality risk for the first 2 days after the event (adjusted hazard ratio of 17.6), but this risk declined rapidly post-infarct (hazard ratio of 1.4 beyond 1 month after the MI event). In contrast, major bleeding had a prolonged association with mortality risk (hazard ratio of 3.5) which remained fairly steady over time throughout 1 year. After accounting for baseline predictors of mortality, major bleeds and MI have similar overall strength of association with mortality in the first year after ACS. MI is correlated with a dramatic increase in short-term risk, whereas major bleeding correlates with a more prolonged mortality risk.