Influence of Diabetes Mellitus on Long-Term Clinical and Economic Outcomes After Coronary Artery Bypass Grafting

Abstract

China has the most patients with diabetes mellitus (DM) in the world and, annually, approximately 1 million Chinese become diabetic. We investigated both clinical and economic outcomes in a large Chinese cohort of diabetic patients undergoing coronary artery bypass graft surgery (CABG). All 9,240 consecutive patients who underwent isolated, primary, elective CABG between January 1999 and December 2008 were included and analyzed for long-term major adverse cardiovascular and cerebrovascular events and economic outcomes up to 2 years after the procedure. The DM patients were divided into DM subgroups controlled by diet (n= 375), medication (n=1,826) or insulin (n= 481). During the study period, the proportion of patients undergoing CABG who have DM increased from 20.1% to 31.8% in China. None of the DM subgroups wasindependently associated with in-hospital death, but DMwas an independent predictor for long-term major adverse cardiovascular and cerebrovascular events (hazard ratio 1.29, 95% confidence interval: 1.14 to 1.46). Medically controlled DM and insulin-dependent DM, but not diet-controlled DM were independent predictors of long-term outcomes after CABG. Cost for initial hospitalization was higher for DM patients (76,782 Ren Min Bi [RMB] versus 65,521 RMB, respectively; p < 0.001). At 2 years after CABG, costs for DM patients were 11,261 RMB (approximately US $1,623) higher than for non-DM patients (p < 0.001). CABG for patients with DM was significantly more expensive and was associated with worse long-term outcomes compared with non-DM patients. The rising incidence of DM, combined with the significant incremental costs represents significant clinical, economic, and social challenges for the Chinese healthcare system.