Antiplatelet therapy and clinical outcomes following myocardial infarction among patients in a U.S. employer-based insurance database

Abstract

BACKGROUND: Estimates of residual cardiovascular risks among patients who have experienced a recent acute myocardial infarction (MI) are predominantly derived from secondary prevention trial populations, patient registries, and population-based cohorts. OBJECTIVE: To generate real-world evidence of antiplatelet treatment and recurrent events following MI in patients on antiplatelet treatment among commercial, employer-based insured patients in a large administrative database. METHODS: This was a retrospective cohort claims database study using the Truven Health MarketScan Commercial Claims and Encounters and Medicare Supplemental databases between 2007-2011. Patients with an acute MI hospitalization with a discharge date between 2008 and 2010 were included. Excluded were those patients with documentation of stroke, transient ischemic attack (TIA), or severe bleeding at or before index hospitalization and with concomitant use of anticoagulant therapy following index hospitalization. Patients treated with clopidogrel following the index MI hospitalization were followed up to 1 year for repeat MI, stroke, and coronary revascularization. RESULTS: Among 33,943 post-MI continuous clopidogrel users without history of stroke, TIA, or bleeding, 22[%] had diabetes, whereas angina and renal impairment were less prevalent (5[%] and 7[%], respectively). Over the 1-year follow-up, 2.4[%] experienced a repeat MI or stroke, and 8.2[%] underwent coronary revascularization. Angina, diabetes, and renal impairment were associated with elevated 1-year risk of repeat MI or stroke. CONCLUSIONS: This study suggests that there is residual cardiovascular risk, although relatively low, in an insured, secondary prevention population on antiplatelet treatment following an MI. In patients with MI, identifying angina, diabetes, and renal impairment may aid risk stratification and guide the effective management of these higher-risk patients.