Background:Patients with diabetes mellitus (DM) have a higher risk of thromboembolic events;however,the optimal duration of dual antiplatelet therapy (DAPT) remains unclear.The goal of this study was to assess the efficacy and safety of various DAPT durations in patients with DM undergoing drug-eluting stent implantation.Methods:We conducted a literature search for randomized controlled trials (RCTs).We searched databases including EMBASE,PubMed,Cochrane Library,and Scopus up to June 2016.Investigators extracted data independently,including outcomes,characteristics,and study quality.A random-effect model was used to pool odds ratios (ORs) with 95％ confidence intervals (CIs) of the clinical outcomes.Results:Six RCTs totaling 6040 patients with DM were included in the study.Shorter-duration DAPT resulted in an increased rate of stent thrombosis (ST) (OR,1.83,95％ CI:1.03-3.26,P =0.04),but did not increase the risk of myocardial infarction (OR,1.33,95％ CI:0.71-2.47,P =0.37),stroke (OR,0.96,95％ CI:0.52-1.77,P =0.90),target vessel revascularization (OR,1.19,95％ CI:0.46-3.07,P =0.71),all-cause death (OR:0.72,95％ CI:0.48-1.09,P=0.12),or cardiac death (OR,0.82,95％ CI:0.49-1.36,P=0.44) significantly.Shorter-duration DAPT was associated with a decreased risk of major bleeding (OR,0.60,95％ CI:0.38-0.94,P =0.02).Conclusion:In patients with DM,longer-duration DAPT had a lower risk of ST,but was associated with an increased bleeding risk.