BACKGROUND: Elevated blood glucose level at admission is associated with worse outcome after a myocardial infarction. The impact of elevated glucose level, particularly fasting glucose, is less certain in non-ST-segment elevation acute coronary syndromes. We studied the relationship between elevated fasting blood glucose levels and outcome across the spectrum of ST-segment elevation and non-ST-segment elevation acute coronary syndromes in a large multicenter population broadly representative of clinical practice.

METHODS: Fasting glucose levels were available for 13 526 patients in the Global Registry of Acute Coronary Events. A multivariate logistic regression analysis was used for assessing the association between admission or fasting glucose level and in-hospital or 6-month outcome, adjusted for the variables from the registry risk scores. RESULTS: Higher fasting glucose levels were associated with a graded increase in the risk of in-hospital death (odds ratios [95% confidence intervals] vs <100 mg>/dL: 1.51 [1.12-2.04] for 100-125 mg/dL, 2.20 [1.64-2.60] for 126-199 mg/dL, 5.11 [3.52-7.43] for 200-299 mg/dL, and 8.00 [4.76-13.5] for > or =300 mg/dL). When taken as a continuous variable, higher fasting glucose level was related to a higher probability of in-hospital death, without detectable threshold and irrespective of whether patients had a history of diabetes mellitus. Higher fasting glucose levels were found to be associated with a higher risk of postdischarge death up to 6 months. The risk of postdischarge death at 6 months was significantly higher with fasting glucose levels between 126 and 199 mg/dL (1.71 [1.25-2.34]) and 300 mg/dL or greater (2.93 [1.33-6.43]), but not within the 200- to 299-mg/dL range (1.08 [0.60-1.95]).

CONCLUSIONS: Short-term and 6-month mortality was increased significantly with higher fasting glucose levels in patients across the spectrum of acute coronary syndromes, thus extending this relation to patients with non-ST-segment elevation myocardial infarction. The relation between fasting glucose level and risk of adverse short-term outcomes is graded across different glucose levels with no detectable threshold for diabetic or nondiabetic patients.