Differential clinical outcomes associated with hypoglycemia and hyperglycemia in acute myocardial infarction

Background— In patients with acute myocardial infarction (AMI), hyperglycemia predicts death, but the prognostic significance of hypoglycemia is controversial. Methods and Results— We evaluated the prognostic significance of hypoglycemia and hyperglycemia in 30 536 AMI patients in a post hoc analysis of 2 large trials of glucose-insulin-potassium therapy in AMI. Glucose levels on admission and at 6 and 24 hours after admission, as well as 30-day mortality, were documented. In separate multivariable Cox models for admission and postadmission glucose, we compared the prognostic value of hypoglycemia (≤70 mg/dL) and hyperglycemia (≥140 mg/dL) with normoglycemia (>70 and P P P =0.37), nor was postadmission hypoglycemia (adjusted hazard ratio 0.96, 95% confidence interval 0.72 to 1.26, P =0.75). Exploratory analyses that redefined hypoglycemia as glucose ≤60 mg/dL showed consistent results, as did analyses restricted to diabetic patients (18% of the study population). Postadmission hypoglycemia was more common in insulin (glucose-insulin-potassium)–treated patients (6.9%) than in untreated patients (3.4%) but did not predict mortality in either subgroup. Conclusions— Both admission and postadmission hyperglycemia predict 30-day death in AMI patients. In contrast, only hypoglycemia on admission predicted death, and this relationship dissipated after admission. These data suggest hypoglycemia may not be a direct mediator of adverse outcomes in AMI patients.