Positive Troponin in Diabetic Ketoacidosis without Evident Acute Coronary Syndrome Predicts Adverse Cardiac Events

BACKGROUND: Elevated troponin I has been associated with increased mortality in critically ill patients without acute coronary syndrome (ACS). However, the prognostic significance of troponin elevation in patients with diabetic ketoacidosis (DKA) without evident ACS has not been studied. METHODS: Retrospective study of all patients admitted to a U.S. tertiary center between 01/98 and 12/00 with DKA and had troponin I level measured. Patients with evidence of ACS or who met the American College of Cardiology/European Society of Cardiology (ACC/ESC) definition for myocardial infarction were excluded. Baseline characteristics, cardiac evaluation and 2 year major adverse coronary event (MACE) rate were compared between patients with positive and negative troponin. RESULTS: Ninety-six patients fulfilled the inclusion criteria of this study, 26 had positive troponin. There were no differences in baseline characteristics between the two groups. After a 2 year follow-up, there was significantly increased mortality in patients with elevated troponin (50.0% versus 27.1%, hazard-ratio (HR) 2.3, 95% confidence interval (CI) 1.2-4.8, p = 0.02). Patients with elevated troponin also had significantly increased MACE rate at 2 years (50.0% versus 28.6%, HR 2.6, 95% CI 1.3-5.3, p = 0.007) driven primarily by mortality. Using Cox Proportional Hazard Analysis, elevated troponin was a predictor of increased MACE after adjusting for confounding variables. (Adjusted HR 2.3, 95% CI 1.1-4.6, p = 0.02) CONCLUSIONS: Elevated troponin I in diabetic patients admitted with DKA identifies a group at very high risk for future cardiac events and mortality. Whether cardiac risk stratification of these patients will improve long term outcome remains to be studied.