Impact of prolonged dual antiplatelet therapy after acute myocardial infarction on 5-year mortality in the FAST-MI 2005 registry.

Background: We document dual antiplatelet therapy (DAPT) use from discharge to 4 years after acute myocardial infarction (AMI), and investigate whether prolonged DAPT (beyond 1 year) is related to 5-year mortality.
Methods: The French Registry of Acute ST-elevation or non-ST-elevation Myocardial Infarction (FAST-MI 2005) included 3670 patients with AMI in 223 French centres. We identified predictors of DAPT (aspirin+clopidogrel) beyond 1 and 2 years, and relation with all-cause 5-year mortality.
Results: Among 3319 (96%) patients with discharge data, 2432 (73%) had DAPT, 582 (17%) single antiplatelet therapy (SAPT), and 305 (9%) no antiplatelet treatment. DAPT decreased from 75% at 1 year to 29% at 4 years, with a corresponding increase in SAPT (p<0.05 for trend). Patients with DAPT were more often male, treated with a drug-eluting stent (DES), and without oral anticoagulants. Independent predictors at 1 year of prolonged DAPT were age<75 years, in-hospital bleeding, history of MI, use of DES, discharge use of beta-blockers or statins and no chronic anticoagulation. Predictors at 2 years were age<75 years, male gender, previous MI, diabetes, DES implantation, no chronic oral anticoagulation. By multivariate analysis, there was no difference in 5-year mortality between those on SAPT vs DAPT at 1 year. DAPT at 2 years was also not significantly related to 5-year mortality (Hazard Ratio 1.3, 95% CI [0.9; 1.8], p=0.21).
Conclusion: Prolonged DAPT in selected AMI patients, observed in 47% at 1 year and 21% at 2 years, had no impact on 5-year mortality. These findings do not support the use of DAPT beyond 1 year after an initial ACS.
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