Clinical question: Are elevated fasting blood glucose levels independently associated with poor outcomes in all types of acute coronary syndromes (ACS)?
Background: Elevated admission blood glucose levels have been associated with poor outcomes in ACS patients; however, the role of fasting blood glucose levels in these settings, especially non-ST elevation myocardial infarction (NSTEMI), is unclear. It also is uncertain if one is a better predictor of outcomes than the other.
Study design: Prospective cohort of 57,406 patients in the Global Registry of Acute Coronary Events (GRACE).
Setting: 106 hospitals located in 14 countries in North and South America, Europe, Australia, and New Zealand.
Synopsis: 22,001 admission and 13,526 fasting blood glucose levels were extracted from GRACE and categorized into groups ranging from <100 mg/dL to =300 mg/dL. Multivariate logistic regression analysis of the association between these and the primary outcomes of in-hospital and six-month post-discharge all-cause mortality was carried out.
Fasting glucose levels higher than 100 mg/dL were associated with a linear increase in inpatient mortality (irrespective of diagnosis of diabetes) with an eightfold increase at levels =300mg/dL (17.22% vs. 1.71%). Increased six-month mortality, especially in patients with NSTEMI and STEMI, was also noted. However, this was a nonlinear relationship due to a lower mortality at 200-299 mg/dL, possibly reflecting the higher number of diabetics undergoing treatment in this group.
Admission glucose levels showed a linear increase in inpatient mortality at levels higher than 126 mg/dL. In contrast to fasting levels, admission levels were not associated with poor long-term outcome.
Study limitations included the use of registry data from a subgroup analysis and the possibility that fasting glucose levels in severely ill patients might not be representative of actual metabolic state.
Bottom line: Elevated fasting blood glucose in patients with acute coronary syndromes may portend a worse outcome and may be a better predictor than admission glucose levels.
Citation: Sinnaeve PR, Steg PG, Fox KA, et al. Association of elevated fasting glucose with increased short-term and 6-month mortality in ST-segment elevation and non-ST-segment elevation acute coronary syndromes: the Global Registry of Acute Coronary Events. Arch Intern Med. 2009;169(4):401-409.
— Reviewed for "TH eWire" by Mital Patel, MD, Alraies Chadi, MD, Saurabh Kandpal, MD, Iqbal Masood, MD, Anuradha Ramaswamy, MD, Department of Hospital Medicine, Cleveland Clinic