Fasting Glucose Is an Important Independent Risk Factor for 30-Day Mortality in Patients With Acute Myocardial Infarction

Abstract

Background— Stress hyperglycemia in patients with acute myocardial infarction has been associated with increased mortality. Most studies looked at the relationship between admission glucose (AG) and outcome; limited information is available about the clinical significance of fasting glucose (FG). Methods and Results— We prospectively studied the relationship between FG and 30-day mortality in 735 nondiabetic patients with acute myocardial infarction. FG (≥8-hour fast within 24 hours of admission) and AG were measured in each patient. At 30 days, 9 deaths (2%) occurred in patients with normal FG, and 11 (10%), 14 (13%), and 31 (29%) deaths occurred in the first, second, and third tertiles of elevated FG, respectively. Compared with normal FG (<110 mg/dL), the adjusted OR for 30-day mortality progressively increased with higher tertiles of elevated FG (first tertile, 4.6; 95% CI, 1.7 to 12.7; P =0.003; second tertile, 6.4; 95% CI, 2.5 to 16.6; P <0.0001; third tertile, 11.5; 95% CI, 4.7 to 20.0; P <0.0001). Compared with patients categorized as having normal AG (<140 mg/d), the adjusted ORs for tertiles of elevated AG were as follows: first tertile, 1.4 (95% CI, 0.5 to 3.8; P =0.54); second tertile, 3.0 (95% CI, 1.3 to 7.0; P =0.01); and third tertile, 4.4 (95% CI, 2.0 to 9.7; P <0.0001). Compared with patients with normal FG and AG, the adjusted ORs for 30-day mortality were 0.71 (95% CI, 0.15 to 3.4; P =0.67) in patients with elevated AG and normal FG, 3.4 (95% CI, 1.1 to 10.4; P =0.03) for patients with normal AG glucose and elevated FG, and 9.6 (95% CI, 3.5 to 26.0; P <0.0001) for patients with both elevated FG and AG. Comparing nested models showed that including AG failed to improve the prediction of the model based on FG (χ 2 =5.4, 3 df , P =0.15). In contrast, the addition of FG classes to the model based on AG improved model prediction (χ 2 =22.4, 3 df , P <0.0001). Conclusions— There is a graded relation between elevated FG and AG and 30-day mortality in patients with acute myocardial infarction. FG is superior to AG in the assessment of short-term risk.