Glycated Hemoglobin vs Fasting Plasma Glucose as a Predictor of Left Ventricular Dysfunction After ST-Elevation Myocardial Infarction

Background: The World Health Organization and the American Diabetes Association recommend a level of glycated hemoglobin (HbA1c) >= 6.5% as diagnostic for diabetes. However, concordance between fasting plasma glucose (FPG) and HbA1c levels in acutely unwell patients is unknown. Furthermore, the prognostic value of HbA1c for left ventricular (LV) dysfunction is unclear. This study aimed to evaluate the concordance between HbA1c levels and FPG in consecutive patients with acute ST-elevation MI (STEMI) and compare their prognostic value in predicting LV dysfunction and elevated filling pressures on echocardiography. Methods: A total of 142 patients with a first incidence of STEMI were prospectively recruited. LV diastolic function was defined as mean septal and lateral early diastolic velocities (average e'); filling pressure was the ratio of transmitral E velocity to average e' (average E/e'). Results: Mean FPG and HbA1c levels were 7.7 +/- 2.8 mmol/L and 6.5% +/- 1.6%, respectively. Of 109 patients without previous diabetes, HbA1c levels identified an additional 18 patients (16.5%) as having diabetes, and the concordance with FPG was poor. Between diabetic and nondiabetic patients, there were no differences in LV end-diastolic volume (116 +/- 37 vs 118 +/- 43 mL; P = 0.78), end-systolic volume (69 +/- 33 vs 68 +/- 35 mL; P = 0.93), and ejection fraction (42 +/- 12 vs 44 +/- 11%; P = 0.49). On multivariable analyses, average e' was independently associated with HbA1c (beta = -0.161; P = 0.045) but not FPG (P = 0.82). Similarly, average E/e' was independently associated with HbA1c (beta = 0.168; P = 0.04) but not FPG (P = 0.32). Receiver operating characteristic curve analysis showed that an HbA1c cutoff of 6.4% (area under the curve, 0.68; P = 0.002) was associated with an elevated LV filling pressure. Conclusions: Only HbA1c was independently associated with impaired LV diastolic function and increased filling pressures after STEMI.