Ten-Year Outcomes of Patients with Left Main Coronary Artery Disease and Diabetes Mellitus Treated with Percutaneous Coronary Intervention

<b>Background/Objectives:</b> Long-term outcomes of patients with left main coronary artery (LMCA) disease and diabetes mellitus (DM) undergoing percutaneous coronary intervention (PCI) are incompletely investigated. The aim of this study was to assess the 10-year clinical outcomes after PCI according to diabetic status and antidiabetic therapy in patients with LMCA. <b>Methods:</b> This study represents a pooled analysis of two randomized trials (<i>n</i> = 1257 patients) on LMCA PCI focused on the prespecified subgroups of diabetic patients. Patients were categorized in groups according to the diabetic status and antidiabetic therapy (oral drugs or insulin therapy). The primary endpoint was 10-year all-cause mortality. <b>Results:</b> Overall, 361 patients had DM (246 patients on oral antidiabetic drugs and 115 patients on insulin therapy) and 896 patients had no DM. At 10 years, 477 patients died: 291 nondiabetic patients (35.7%), 111 diabetic patients (49.5%) on oral antidiabetic drugs and 75 diabetic patients (70.0%) on insulin therapy (hazard ratio [HR] = 1.57, 95% confidence interval [1.26-1.96]; <i>p</i> < 0.001 for diabetic patients on oral antidiabetic drugs vs. nondiabetic patients; HR = 2.80 [2.17-3.61]; <i>p</i> < 0.001 for diabetic patients on insulin therapy vs. nondiabetic patients; HR = 1.78 [1.33-2.39]; <i>p</i> <0.001 for diabetic patients on insulin therapy vs. diabetic patients on oral antidiabetic drugs). The 10-year incidence of myocardial infarction was higher in diabetic patients on insulin therapy (10.0%) versus diabetic patients on oral antidiabetic drugs (3.0%). There were no significant differences between the groups regarding the 10-year incidence of definite stent thrombosis, coronary artery bypass graft surgery, repeat PCI or stroke. <b>Conclusions:</b> In patients with LMCA disease undergoing PCI, DM was associated with a higher 10-year incidence of all-cause mortality than patients without DM with the worst outcomes observed in diabetic patients on insulin therapy.