Benefits and Risks of Prolonged Duration Dual Antiplatelet Therapy (Clopidogrel and Aspirin) After Percutaneous Coronary Intervention in High-Risk Patients With Diabetes Mellitus.

The efficacy and safety of prolonged (>1-year) dual antiplatelet therapy (DAPT) duration in high-risk patients with diabetes mellitus (DM) undergoing percutaneous coronary intervention (PCI) remain unknown. All patients undergoing PCI at Fuwai hospital between January 2013 and December 2013 were prospectively enrolled into the Fuwai PCI registry. A total of 3,696 high-risk diabetics patients with at least one additional atherothrombotic risk factor were screened for inclusion. The primary efficacy outcome was the composite of all-cause mortality, myocardial infarction, or stroke. The median follow-up duration was 887 days. 69.8% of DM patients were on DAPT at 1 year without discontinuation. Based on multivariate Cox regression model and inverse probability of treatment weighting (IPTW) analysis, long-term (>1-year) DAPT reduced the risk of primary efficacy outcome (1.7% vs 4.1%; adjusted hazard ratio [adjHR]: 0.382, 95% confidence interval [CI]: 0.252 to 0.577; IPTW-HR: 0.362 [0.241 to 0.542]), as well as cardiovascular death and definite/probable stent thrombosis, compared with short-course (≤1-year) DAPT. Risk of the safety end point of clinically relevant bleeding (adjHR: 0.920 [0.467 to 1.816]; IPTW-HR: 0.969 [0.486 to 1.932]) was comparable between longer DAPT and shorter DAPT. A lower number of net clinical benefit adverse outcomes was observed with >1-year DAPT versus ≤1-year DAPT (adjHR: 0.471 [0.331 to 0.671]; IPTW-HR: 0.462 [0.327 to 0.652]), which appeared increasingly favorable in those with multiple atherothrombotic risk characteristics. In high-risk patients with DM receiving PCI who were event free at 1 year, DAPT prolongation resulted in significant reduction in the risk of ischemic events not offset by increase of clinically meaningful bleeding events, thereby achieving a net clinical benefit. Extending DAPT beyond the period mandated by guidelines seems reasonable in high-risk DM patients not deemed at high bleeding risk.