Effect of early clopidogrel discontinuation on rehospitalization in acute coronary syndrome: Results from two distinct patient populations

Abstract

Results of a study of the association between early discontinuation of clopidogrel therapy and rehospitalization rates among patients with acute coronary syndrome (ACS) are reported. In a retrospective observational study, analyses of two nationally representative cohorts of adults hospitalized for acute myocardial infarction (AMI) or coronary stent insertion were conducted to assess risk factors for ACS-related adverse outcomes (rehospitalization for AMI or coronary revascularization) during the 12 months after completion of an initial 28-day course of clopidogrel therapy. Case data were sourced from a commercial insurance claims database, a pharmacy administrative claims database, and a combined dataset that linked hospital discharge and outpatient service data; a time-varying method was used to differentiate adverse events occurring "on" and "off" clopidogrel therapy. One cohort analysis (n = 42,757) indicated that patients who discontinued clopidogrel early (i.e., within 12 months of index discharge) were at significantly increased risk for ACS-related rehospitalization during the 12-month study period (hazard ratio [HR] = 1.11; 95% confidence interval [CI], 1.02-1.20; p < 0.05). In the other cohort analysis (n = 3,171), early clopidogrel discontinuation was associated with an increased risk of rehospitalization or inpatient death (HR = 1.75; 95% CI, 1.59-1.91; p < 0.0001). Observational evidence from analyses of data on two large cohorts of patients with primarily employer-sponsored health insurance suggests that early discontinuation of clopidogrel therapy after hospitalization for AMI or coronary stent insertion is associated with a significant increase in the risk of ACS-related rehospitalization within the 12-month postdischarge period.