Fasting glucose is an important independent risk factor for 30-day mortality in patients with acute myocardial infarction: a prospective study

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 (> or =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 (chi2=5.4, 3 df, P=0.15). In contrast, the addition of FG classes to the model based on AG improved model prediction (chi2=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.