Do Diabetics Benefit From Prolonged DAPT After Stenting?
Does diabetes mellitus (DM) help identify patients who may benefit from prolonging dual antiplatelet therapy (DAPT) >12 months after percutaneous coronary intervention (PCI)?
This was a retrospective analysis of all patients who received a coronary stent at any Veterans Affairs’ (VA) facility in the United States between April 2002 and September 2006, and who were alive 12 months after their index PCI. During this time frame, only first-generation drug-eluting stents (DES) were available. Subjects free of the clinical outcomes at 1 year were followed to September 2007, with a maximum follow-up of 4 years after their index PCI. Patients were stratified into three groups: no DM, diabetes and treated with oral medications or no medications, and diabetes treated with insulin. Clopidogrel use was defined as either prolonged (>12 months of use after the index PCI) or ≤12 months of use after the index PCI. The primary endpoint was the combined endpoint of death or MI in the 1-4 years after PCI.
The study population consisted of 28,849 patients who were alive 12 months after their index PCI. Among patients receiving DES, death or MI occurred in 150 (22%) patients with insulin-treated DM (hazard ratio [HR], 1.97; p < 0.0001 compared to no DM), 393 (16%) with DM not requiring insulin (HR, 1.31; p < 0.0001 compared to no DM), and 129 (12%) with no DM. Among DM patients not requiring insulin, there was a significant interaction for prolonged clopidogrel and stent type with a significantly greater reduction in the risk of death or MI in DES versus BMS (interaction p-value = 0.005). There were similar trends in patients with insulin-treated DM.
The authors concluded that there is an interaction between diabetes and stent type. Only patients with diabetes receiving a DES had lower risk of death or MI with prolonged clopidogrel.
This is an important study that makes progress toward the identification of factors that may be associated with favorable outcomes from prolonged DAPT. The limitations of this retrospective analysis aside, the authors provide an argument for prolonged DAPT in diabetics managed with first-generation DES. Future studies should characterize additional characteristics that may help select patients who will benefit from prolonged DAPT. Future studies should also clarify outcomes in those receiving newer stent platforms.
Keywords: Acute Coronary Syndrome, Diabetes Mellitus, Drug-Eluting Stents, Insulin, Metabolic Syndrome X, Platelet Aggregation Inhibitors, Risk, Secondary Prevention, Stents, Ticlopidine
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