INTERPRETING THE CHARISMA STUDY: What is the role of dual antiplatelet therapy with clopidogrel and aspirin?

The Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance (CHARISMA) study (N Engl J Med 2006; 354:1706-1717, J Am Coil Cardiol 2007; 49:1982-1988) assessed the effect of dual antiplatelet therapy with clopidogrel (Plavix) and aspirin in patients at risk of atherothrombotic events. At a median of 28 months, the rate of the primary efficacy end point (a composite of myocardial infarction, stroke, and death from cardiovascular causes) was not significantly lower in the group receiving clopidogrel plus aspirin than in the group receiving placebo plus aspirin. However, one subgroup may have derived some benefit from the combination: those at higher risk owing to a history of myocardial infarction, ischemic stroke, or symptomatic peripheral arterial disease.