摘要OBJECTIVE To investigate the optimal duration of dual antiplatelet therapy(DAPT)in patients with diabetes mellitus(DM)requiring complex percutaneous coronary intervention(PCI).METHODS A total of 2403 patients with DM who underwent complex PCI from January to December 2013 were consecutive-ly enrolled in this observational cohort study and divided according to DAPT duration into a standard group(11-13 months,n = 689)and two prolonged groups(13-24 months,n = 1133;>24 months,n = 581).RESULTS Baseline characteristics,angiographic findings,and complexity of PCI were comparable regardless of DAPT durat-ion.The incidence of major adverse cardiac and cerebrovascular event was lower when DAPT was 13-24 months than when it was 11-13 months or>24 months(4.6%vs.8.1%vs.6.0%,P = 0.008),as was the incidence of all-cause death(1.9%vs.4.6%vs.2.2%,P = 0.002)and cardiac death(1.0%vs.3.0%vs.1.2%,P = 0.002).After adjustment for confounders,DAPT for 13-24 months was asso-ciated with a lower risk of major adverse cardiac and cerebrovascular event[hazard ratio(HR)= 0.544,95%CI:0.373-0.795]and all-cause death(HR = 0.605,95%CI:0.387-0.944).DAPT for>24 months was associated with a lower risk of all-cause death(HR = 0.681,95%CI:0.493-0.942)and cardiac death(HR = 0.620,95%CI:0.403-0.952).The risk of major bleeding was not increased by prolonging DAPT to 13-24 months(HR = 1.356,95%CI:0.766-2.401)or>24 months(HR = 0.967,95%CI:0.682-1.371).CONCLUSIONS For patients with DM undergoing complex PCI,prolonging DAPT might improve the long-term prognosis by reducing the risk of adverse ischemic events without increasing the bleeding risk.