title: 2015 Young Surgeon's Award Winner: Long-term Prognosis in Patients with Diabetes Mellitus after Coronary Artery Bypass Grafting: A Propensity-Matched Study.
abstract: BACKGROUND
  We aimed to determine the impact of diabetes mellitus (DM) on long-term survival after coronary artery bypass grafting (CABG) in patients with multivessel coronary artery disease.
  
  
  METHODS
  A retrospective review was conducted for 5720 consecutive patients who underwent isolated first CABG between 1982 and 1999. Outcomes were reviewed to include in-hospital mortality and long-term survival. Mean follow-up was 13.0 ± 5.8 years. To obtain comparable subgroups, 561 diabetic patients were matched with 561 non-diabetic controls based on estimated propensity scores.
  
  
  RESULTS
  Mean age was 59.3 ± 9.1 years with 4373 (76.5%) males. Amongst 5720 patients, 1977 (34.6%) had DM. Hypertension and dyslipidaemia were the most common cardiovascular comorbidities, present in 2920 (51.0%) and 2664 patients (46.6%) respectively. Emergency surgery was performed in 563 patients (9.8%). In-patient mortality occurred in 115 patients (2.0%), 48 (2.4%) in the DM group and 67 (1.8%) in the non-DM group, (P = 0.102). In the unmatched cohort, overall 20-year survival rates were 30.9 ± 1.6% in diabetics and 49.2 ± 1.0% in non-diabetics (P <0.001). Freedom from cardiac mortality at 20 years was 56.0 ± 2.0% in diabetics and 68.4 ± 1.0% in non-diabetics (P <0.001). In the propensity-matched group, overall 20-year survival rates were 35.4 ± 2.5% in diabetics and 48.9 ± 2.9% in non-diabetics (P <0.001). Freedom from cardiac mortality at 20 years was 57.8 ± 3.0% in diabetics and 70.2 ± 2.9% in non-diabetics (P = 0.001). Multivariable Cox regression analysis identified age (hazard ratio (HR): 1.03/year), female gender (HR: 1.43), DM (HR: 1.51), previous myocardial infarction (HR: 1.54) and left ventricular ejection fraction (LVEF) <35% (HR: 2.60) as independent factors influencing long-term cardiac mortality.
  
  
  CONCLUSIONS
  Despite low operative mortality, long-term survival and freedom from cardiac death are significantly lower in patients with DM compared to non-diabetics. Aggressive treatment of DM, cardiovascular comorbidities and smoking cessation are essential to improve long-term survival in diabetic patients.
authors.affiliation: National Heart Centre Singapore, Singapore.
authors.forename: Philip Yk
authors.initials: PY
authors.lastname: Pang
authors.forename: Yeong Phang
authors.initials: YP
authors.lastname: Lim
authors.forename: Kim Kiat
authors.initials: KK
authors.lastname: Ong
authors.forename: Yeow Leng
authors.initials: YL
authors.lastname: Chua
authors.forename: Yoong Kong
authors.initials: YK
authors.lastname: Sin
mesh_terms: D000367:Age Factors; D000368:Aged; D001363:Awards and Prizes; D016022:Case-Control Studies; D015897:Comorbidity; D001026:Coronary Artery Bypass; D003324:Coronary Artery Disease / Q000453:epidemiology / Q000601:surgery*; D003920:Diabetes Mellitus / Q000453:epidemiology*; D050171:Dyslipidemias / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000453:epidemiology; D011379:Prognosis; D057216:Propensity Score; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012737:Sex Factors; D012846:Singapore / Q000453:epidemiology; D013318:Stroke Volume