Prolonged Dual Antiplatelet Therapy and Diabetes

Study Questions:

What is the safety and efficacy of prolonged dual antiplatelet therapy (DAPT) in patients with diabetes?

Methods:

The investigators reported on the diabetic subset of the DAPT trial. In this study, patients undergoing coronary stent placement and free of ischemic or bleeding events after 12 months of treatment with open-label thienopyridine plus aspirin were randomized to continued thienopyridine or placebo, in addition to aspirin, for 18 more months. This paper describes the cohort of patients with diabetes (n = 3,391), compared with patients without diabetes (n = 8,257).

Results:

Patients with diabetes had an increased composite outcome of death, myocardial infarction (MI), or stroke (6.8% vs. 4.3%, p < 0.001), and increased death (2.5% vs. 1.4%, p < 0.001), and MI (4.2% vs. 2.6%, p < 0.001) compared to those without diabetes. Patients with diabetes had a more modest reduction in the composite endpoint of major adverse cardiac and cerebrovascular events (MACCE) (interaction p = 0.03) compared with patients without diabetes. In patients with diabetes, MACCE occurred in 6.6% with DAPT versus 7.0% for placebo (p = 0.55), while for patients without diabetes, the corresponding rates were 3.3% versus 5.2% (p < 0.001). Among patients with diabetes, DAPT was associated with an attenuated reduction in MI (3.5% vs. 4.8%, p = 0.058), compared with nondiabetics (1.6% vs. 3.6%, p < 0.001; MI, p for interaction = 0.02). Bleeding risk with continued thienopyridine was similar amongst patients with or without diabetes.

Conclusions:

The authors concluded that the benefit of prolonged DAPT is attenuated in patients with diabetes.

Perspective:

The DAPT trial demonstrated a reduction in MI and excess of bleeding events with prolonged DAPT without any reduction in mortality. This study suggests that while the risk of ischemic events is higher in diabetics, the benefit of DAPT is attenuated in this patient cohort with no difference in survival or the composite primary endpoint (MACCE), arguing against routine prolonged DAPT in patients with diabetes who are undergoing coronary stenting.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Prevention

Keywords: Aspirin, Diabetes Mellitus, Hemorrhage, Mortality, Myocardial Infarction, Myocardial Ischemia, Platelet Aggregation Inhibitors, Risk, Secondary Prevention, Stents, Stroke


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