AbstractOBJECTIVESDiabetics may have diminished survival after coronary artery bypass grafting even with multiple arterial revascularization. We compared multi-arterial versus single-arterial grafting (SAG) survival in diabetic and non-diabetic patients undergoing primary isolated bypass surgery.METHODSThis is a retrospective analysis of the Australian and New Zealand Society of Cardiac-Thoracic Surgical Database from June 2001 to January 2020. Patients were classified as having either single or multiple arterial grafting irrespective of the number of venous grafts. The end points were long-term all-cause mortality and 30-day clinical outcomes, which was compared in 1:1 propensity score-matched patients. Cox regression model was used to assess interactions between diabetes and the treatment effect of multi-arterial grafting, reported as hazard ratios (HRs) and confidence intervals (CIs). Short-term outcomes were compared with McNemar’s pairedt-test.RESULTSFrom 69 624 patients, matching generated 17 474 non-diabetic and 10 989 diabetic patient pairs. At a median [interquartile range] of 5.9 [3.2–9.6] years postoperative, mortality was significantly lower after multi-arterial grafting for both diabetic (HR, 0.83; 95% CI, 0.76–0.90,P< 0.001) and non-diabetic (HR, 0.88; 95% CI, 0.82–0.95;P< 0.001) cohorts than SAG. The incidence of 30-day myocardial infarction was significantly higher in single than multiple arterial grafting for both cohorts (diabetic,P= 0.029; non-diabetic,P< 0.001). The interaction analysis suggested an insignificant effect of diabetes (P= 0.55) on the observed survival advantage. Further stratification by diabetic management generated consistent results.CONCLUSIONSMulti-arterial grafting was associated with improved overall survival compared to SAG for both non-diabetic and diabetic patients.