The association of glycated hemoglobin A1c with coronary artery disease, myocardial infarction, and severity of coronary lesions

Glycated hemoglobin A1c (HbA1c) has been recognized as a predictor of cardiovascular events. However, the relationship between HbA1c and coronary artery disease (CAD) in the Chinese population has yet to be systematically explored. In addition, factors associated with HbA1c were generally analyzed linearly, thereby failing to appreciate more complex nonlinear associations. The study aimed to evaluate the relationship between the HbA1c value and the presence and severity of coronary artery stenosis. A total of 7192 consecutive patients who underwent coronary angiography were enrolled. Their biological parameters, including HbA1c, were measured. The severity of coronary stenosis was evaluated using Gensini score. After correcting for baseline confounding factors, a multivariate logistic regression analysis was used to evaluate the relationship between HbA1c and CAD severity. Restricted cubic splines were applied to explore the relation of HbA1c with the presence of CAD, myocardial infarction (MI), and the severity of coronary lesions. HbA1c was significantly associated with the presence and severity of CAD in patients without diagnosed diabetes (odds ratio: 1.306, 95% confidence interval: 1.053–1.619, p = 0.015). Spline analysis showed a U-shaped association of HbA1c with the presence of MI. Both HbA1c > 7.2% and HbA1c < 5.7% were associated with the presence of MI. In conclusion, HbA1c value was highly associated with the severity of coronary artery stenosis in the whole study population, and in CAD patients without diagnosed diabetes. Compared with patients with HbA1c levels between 6.0% and 7.0%, HbA1c < 5.7% and HbA1c > 7.2% were associated with higher presence of MI.