P2770In-hospital prognostic relevance of acute on chronic glycemic ratio in patients with acute myocardial infarction

Abstract

Background/Introduction: Acute hyperglycemia is common in acute myocardial infarction (AMI), and has been recognized as independent determinant of adverse outcomes in patients with and without diabetes mellitus (DM). Acute hyperglycemia has been shown to be a powerful predictor of poor prognosis particularly in non-diabetic patients, thus emphasizing the importance of acute glucose level rise, compared to its chronic elevation, as a predisposing factor for adverse prognosis. As information on chronic glucose levels can be estimated by the glycosylated hemoglobin (HbA1c) value, the combined information provided by acute and chronic glycemic values could better reflect prognosis in AMI patients than admission glycemia or DM status alone, by reflecting the "true" acute glycemic increase. This could be particularly relevant in DM patients, in whom high admission glucose levels do not necessarily indicate the presence of acute hyperglycemia. Purpose(s): We prospectively investigated the association between acute on chronic (A/C) glycemic ratio and in-hospital outcome in an unselected cohort of consecutive AMI patients. Method(s): We measured blood glucose and HbA1c levels at hospital admission. Average chronic glucose levels (mg/dl) were estimated by HbA1c, according to the formula: 28.7 x HbA1c (%) - 46.7. In all patients, the A/C glycemic ratio was calculated considering blood glucose on admission and estimated chronic glucose levels. The primary endpoint of the study was the combination of in-hospital mortality, acute pulmonary edema, and cardiogenic shock. Infarct size, estimated by troponin I peak value, was our secondary endpoint. Result(s): 1553 AMI patients (747 STEMI and 806 NSTEMI; 22% with DM) were included in the study. Patients in the highest tertile were older, more likely to have STEMI, DM, lower eGFR and LVEF, and higher TIMI risk score than patients in the lower tertiles. 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 also observed in troponin I peak value (15+/-34 ng/ml, 34+/-66 ng/ml, and 68+/-131 ng/ml, respectively; P<0.0001). At reclassification analyses, the A/C glycemic ratio provided the best prognostic power in predicting the occurrence of primary endpoint, when compared to acute glycemia, in the overall population (NRI 12% [4-20], P=0.003) and, particularly, in patients with DM (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. Conclusion(s): The A/C glycemic ratio significantly improved in-hospital outcome prediction beyond acute glycemia. This was particularly relevant in patients with DM, in whom A/C glycemic ratio should be evaluated in order to identify the true acute hyperglycemia associated with a poor prognosis. (Figure Presented).