Long-term dual antiplatelet therapy (DAPT) did not reduce the risk of major adverse cardiac events (MACE) but did increase the risk of bleeding among patients with drug eluting stents with and without diabetes, when compared with short-term DAPT, a recent study showed. The meta-analysis of 6 trials included 11,473 randomized patients and compared the clinical outcomes between short-term (≤6 months) and long-term (12 months) DAPT after placement of a drug eluting stent in patients with and without diabetes. Primary outcome was 1-year risk of MACE. Researchers found:

• 3,681 (32.1%) patients had diabetes; 7,708 (67.2%) did not.

• Diabetes was an independent predictor of MACE (HR, 2.30).

• At 1-year follow-up, long-term DAPT was not associated with a decreased risk of MACE compared with short-term DAPT in patients with (HR, 1.05) or without (HR, 0.97) diabetes.

• Risk of myocardial infarction (MI) did not differ between the 2 DAPT regimens.

• A lower risk of definite/probable stent thrombosis was observed with long-term DAPT among patients with than without diabetes.

Citation: Gargiulo G, Windecker S, da Costa BR, et al. Short term versus long term dual antiplatelet therapy after implantation of drug eluting stent in patients with and without diabetes: Systematic review and meta-analysis of individual participant data from randomised trials. [Published online ahead of print November 3, 2016]. BMJ. doi:10.1136/bmj.i5483.

Commentary: The use of a drug eluting stent (DES) compared with a bare metal stent (BMS) has reduced the risk for restenosis and repeat revascularization procedures in patients with coronary artery disease. A DES, however, may have an increased risk for in-stent thrombosis compared with a BMS due to a delay in endothelialization of a DES requiring prolonged treatment with dual antiplatelet therapy (DAPT); usually low dose aspirin and clopidogrel for 1 year. The risk for late in-stent thrombosis with a newer generation DES appears to be lower than noted with older stents. This study is a meta-analysis of 6 trials comparing major cardiovascular event rates after 6 months compared to 1 year of DAPT after placement of a DES, with a particular focus on diabetic patients. Diabetic patients were shown to have a higher rate of major cardiovascular events compared to non-diabetics. The rate of major cardiovascular events was similar after 6-month or 1-year treatment with DAPT despite the fact the in-stent thrombosis was reduced with 1-year therapy compared to 6 month. Bleeding risk was significantly higher with 1 year of DAPT compared to 6 months. This suggests that it is safe to treat patients for only 6 months of DAPT after DES placement, and may be a preferable treatment protocol than current therapy in patients at high risk for bleeding. —Matthew Sorrentino, MD