Diabetes Mellitus and Prevention of Late Myocardial Infarction After Coronary Stenting in the Randomized Dual Antiplatelet Therapy Study

BACKGROUND: Patients with diabetes mellitus (DM) are at high risk for recurrent ischemic events after coronary stenting. We assessed the effects of continued thienopyridine among patients with DM participating in the Dual Antiplatelet Therapy (DAPT) Study as a prespecified analysis. METHODS AND RESULTS: After coronary stent placement and 12 months treatment with open-label thienopyridine plus aspirin, 11 648 patients free of ischemic or bleeding events and who were medication compliant were randomly assigned to continued thienopyridine or placebo, in addition to aspirin, for 18 more months. After randomization, patients with DM (n=3391), in comparison with patients without DM (n=8257), had increased composite outcome of death, myocardial infarction (MI), or stroke (6.8% versus 4.3%, P<0.001), increased death (2.5% versus 1.4%, P<0.001), and MI (4.2% versus 2.6%, P<0.001). Among patients with DM, in a comparison of continued thienopyridine versus placebo, rates of stent thrombosis were 0.5% versus 1.1%, P=0.06, and rates of MI were 3.5% versus 4.8%, P=0.058; and among patients without DM the rates were 0.4% versus 1.4%, P<0.001 (stent thrombosis, P interaction=0.21) and 1.6% versus 3.6%, P<0.001 (MI, P interaction=0.02). Bleeding risk with continued thienopyridine was similar among patients with or without DM (interaction P=0.61). CONCLUSIONS: In patients with DM, continued thienopyridine beyond 1 year after coronary stenting is associated with reduced risk of MI, although this benefit is attenuated in comparison with patients without DM. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00977938.