Introduction: Acute hyperglycemia is a powerful predictor of poor prognosis in acute myocardial infarction (AMI), particularly in patients without diabetes mellitus (DM). This emphasizes the importance of an acute glycemic rise, rather than glycemia level at admission alone.
Hypothesis: We investigated whether, in AMI, the combined evaluation of acute and chronic glycemic levels, as compared to admission glycemia alone, may have a better prognostic value
Methods: We prospectively measured admission glycemia and estimated average chronic glucose levels by glycosylated hemoglobin (mg/dl), and calculated the acute on chronic (A/C) glycemic ratio in 1,553 consecutive AMI patients. The primary endpoint was the combination of in-hospital mortality, acute pulmonary edema, and cardiogenic shock.
Results: The primary endpoint rate increased in parallel with A/C glycemic ratio tertiles (5%, 8% and 20%, respectively; P for trend <0.0001). A parallel increase was observed in troponin I peak value (15±34 ng/ml, 34±66 ng/ml, and 68±131 ng/ml, respectively; P<0.0001). At multivariable analysis, A/C glycemic ratio remained an independent predictor of the primary endpoint and of a larger infarct size, even after adjustment for major confounders. At reclassification analyses, A/C glycemic ratio showed the best prognostic power in predicting primary endpoint as compared to glycemia at admission in the entire population (NRI 12% [4-20], P=0.003) and, particularly, in DM patients (NRI 27% [14-40], P<0.0001). Figure 1 shows the OR for the primary endpoint of acute glycemia and A/C glycemic ratio tertiles in patients with and without DM.
Conclusions: In AMI patients, A/C glycemic ratio is a better predictor of in-hospital morbidity and mortality than glycemia at admission alone. This parameter may be particularly useful in DM patients to identify true stress hyperglycemia.