Optimal duration of dual antiplatelet therapy after second-generation drug-eluting stent implantation in patients with diabetes: The SECURITY (Second-Generation Drug-Eluting Stent Implantation Followed By Six- Versus Twelve-Month Dual Antiplatelet Therapy)-diabetes substudy

Background/objectives: The randomized SECURITY (Second-Generation Drug-Eluting Stent Implantation Followed by Six- Versus Twelve-Month Dual Antiplatelet Therapy) trial showed the non-inferiority of 6 vs. 12-month DAPT after percutaneous coronary intervention (PCI) with second-generation DES in a low-risk population. Nevertheless, diabetes mellitus (DM) remained a major predictor of adverse cardiovascular events. We aimed to assess the interaction between DAPT duration and outcome in DM patients.

Methods: All diabetic patients included in the SECURITY trial treated by second-generation DES PCI were analyzed. The primary endpoint was a composite of cardiac death, myocardial infarction (MI), stroke, definite or probable stent thrombosis (ST), or Bleeding Academic Research Consortium (BARC) type 3 or 5 bleeding at 12months. The main secondary endpoint was a composite of cardiac death, MI, stroke, definite or probable ST, or BARC type 2, 3, or 5 bleeding at 24months.

Results: Four hundred-twenty nine DM patients received either 6 (n=206) or 12 (n=223) months of DAPT. The primary endpoint occurred in 3.9% and 5.4% of patients in the 6 and 12-month DAPT group, respectively (log-rank test p=0.83). Similarly, no statistically significant difference in the secondary endpoint was observed between the two study groups (5.4% vs. 7.6%, p=0.620). Stent thrombosis rate was low irrespective of DAPT duration at both 12 (0.5% vs. 0.4%; p=0.804) and between 12 and 24months of follow-up (0.5% vs. 0%, p=0.291). At multivariable analysis, female gender (HR: 3.42; 95% CI 1.32-8.85; p=0.011 and HR 2.28; 95% CI 1.09-4.75; p=0.027) and insulin-treated diabetes mellitus (HR: 2.62; 95% CI 1.15-6.75; p=0.004 and HR: 2.23; 95% CI 1.09-6.33; p=0.003) were independent predictors of both primary and secondary endpoint.

Conclusions: In diabetic patients treated by second-generation DES PCI, we failed to find any additional benefit of prolonging DAPT beyond 6months, regardless of insulin-requiring status.