title: Is admission blood glucose concentration a more powerful predictor of mortality after myocardial infarction than diabetes diagnosis? A retrospective cohort study.
abstract: OBJECTIVE
  To explore the relative association of admission blood glucose levels and antecedent diabetes on early and long-term survival in a contemporary UK population of patients with ST elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI).
  
  
  METHODS
  Retrospective cohort study based on the Myocardial Ischaemia National Audit Project dataset.
  
  
  METHODS
  Tertiary care centre.
  
  
  METHODS
  4111 (20.3% known diabetes) consecutive patients admitted with acute myocardial infarction (58.3% STEMI) between October 2002 and September 2008.
  
  
  METHODS
  All-cause mortality at 30 days and 1 year. The relative association of admission blood glucose and of antecedent diabetes with mortality was assessed using multivariate Cox regression analysis. Furthermore, we compared these relationships in patients with STEMI to those with NSTEMI.
  
  
  RESULTS
  By 30 days and 1 year, 409 (9.9%) and 677 (16.5%) of patients died. After adjusting for covariates, diabetes did not show independent association with mortality at any time point, in the entire cohort (HR 30 days 0.93 (95% CI 0.63 to 1.38); 1 year 1.00 (0.77 to 1.30)) or in subgroups of STEMI (HR 30 days 1.03 (0.65 to 1.64); 1 year 1.08 (0.77 to 1.51)) and NSTEMI (HR 30 days 0.62 (0.26 to 1.50); 1 year 0.87 (0.56 to 1.36)). In contrast, after adjusting for covariates, admission glucose showed robust and independent association with mortality in the entire cohort (HR: 30 days 1.07 (1.04 to 1.10); 1 year 1.05 (1.03 to 1.08)), and in the subgroup of STEMI (30 days 1.07 (1.03 to 1.10); 1 year 1.07 (1.04 to 1.10)), and NSTEMI (HR 30 days 1.07 (1.00 to 1.14); 1 year 1.02 (0.97 to 1.06)).
  
  
  CONCLUSIONS
  Admission glucose is strongly associated with mortality in all presentations of acute myocardial infarction (AMI), irrespective of established diabetes diagnosis. The increased risk is maintained up to 1 year. Future studies are required to assess the impact of active management of elevated blood glucose in improving mortality in individuals admitted with AMI.
authors.affiliation: Department of Health Sciences, University of Leicester, Leicester, UK.
authors.forename: Nitin Narayan
authors.initials: NN
authors.lastname: Gholap
authors.forename: Rajnikant Laxmishanker
authors.initials: RL
authors.lastname: Mehta
authors.forename: Leong
authors.initials: L
authors.lastname: Ng
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Davies
authors.forename: Kamlesh
authors.initials: K
authors.lastname: Khunti
authors.forename: Iain B
authors.initials: IB
authors.lastname: Squire