Acute
hyperglycemia is a frequent finding in patients presenting to the emergency department (ED) with acute
myocardial infarction (AMI). The prognostic role of
hyperglycemia in diabetic patients with AMI remains controversial. We retrospectively reviewed patients' medical records to obtain demographic data, clinical presentation,
major adverse cardiac events (MACEs), several clinical scores and laboratory data, including the plasma
glucose level at initial presentation and HbA1c levels. The glycemic gap, which represents changes in serum
glucose levels during the index event, was calculated from the
glucose level upon ED admission minus the HbA1c-derived average
glucose (ADAG). We enrolled 331 patients after the review of medical records. An elevated glycemic gap between admission serum
glucose levels and ADAG were associated with an increased risk of mortality in patients. The glycemic gap showed superior discriminative power regarding the development of MACEs when compared with the admission
glucose level. The calculation of the glycemic gap may increase the discriminative powers of established clinical scoring systems in diabetic patients presenting to the ED with AMI. In conclusion, the glycemic gap could be used as an adjunct parameter to assess the severity and prognosis of diabetic patients presenting with AMI. However, the usefulness of the glycemic gap should be further explored in prospective longitudinal studies.