Background/AimsThe aim of this study was to evaluate the impact of diabetes mellitus (DM) on in-hospital and 1-year mortality in patients who suffered acute myocardial infarction (AMI) and underwent successful percutaneous coronary intervention (PCI).MethodsAmong 5,074 consecutive patients from the Korea AMI Registry with successful revascularization between November 2005 and June 2007, 1,412 patients had a history of DM.ResultsThe DM group had a higher mean age prevalence of history of hypertension, dyslipidemia, ischemic heart disease, high Killip class, and diagnoses as non-ST elevation MI than the non-DM group. Left ventricular ejection fraction (LVEF) and creatinine clearance were lower in the DM group, which also had a significantly higher incidence of in-hospital and 1-year mortality of hospital survivors (4.6% vs. 2.8%, p = 0.002; 5.0% vs. 2.5%, p < 0.001). A multivariate analysis revealed that independent predictors of in-hospital mortality were Killip class IV or III at admission, use of angiotensin converting enzyme inhibitors or angiotensin-II receptor blockers, LVEF, creatinine clearance, and a diagnosis of ST-elevated MI but not DM. However, a multivariate Cox regression analysis showed that DM was an independent predictor of 1-year mortality (hazard ratio, 1.504; 95% confidence interval, 1.032 to 2.191).ConclusionsDM has a higher association with 1-year mortality than in-hospital mortality in patients with AMI who underwent successful PCI. Therefore, even when patients with AMI and DM undergo successful PCI, they may require further intensive treatment and continuous attention.