Usefulness of changes in fasting glucose during hospitalization to predict long-term mortality in patients with acute myocardial infarction.

Stress hyperglycemia is a complex phenomenon that incorporates the cumulative effects of multiple factors. Rapid changes in blood glucose may reflect neurohormonal and homodynamic events that affect patient outcome. We prospectively studied the relation between changes in fasting glucose (FG) during a hospital course and long-term mortality in 1,467 nondiabetic patients with acute myocardial infarction. FG was obtained at admission and later during the hospital course and classified at each time point as normal (<100 mg/dl), impaired (100 to 125 mg/dl), or diabetic range (>or=126 mg/dl). The relation between measurements of FG and mortality (median follow-up 30 months) was assessed using Cox models. FG classification improved in 426 (29.0%) and worsened in 248 patients (16.9%) during hospitalization. Mean FG was a better predictor of mortality than baseline or final FG levels alone (C-index 0.670, 0.656, and 0.645, respectively). Changes in FG during hospitalization were strongly associated with changes in mortality risk. Compared to patients with persistent normal FG, the adjusted hazard ratio (HR) for mortality was 2.6 (95% confidence interval [CI] 1.0 to 7.2) for patients in whom FG increased to the diabetic range; the HR was 6.3 (95% CI 4.0 to 10.4) in patients with persistent FG in the diabetic range but decreased substantially when FG normalized during hospitalization (HR 2.7, 95% CI 1.3 to 5.1). In conclusion, persistent increase of FG during hospitalization for acute myocardial infarction has greater prognostic effect than baseline FG. Changes in FG during hospitalization are simple and sensitive indicators of dynamic changes in risk.