Hemoglobin A1c is associated with severity of coronary artery stenosis but not with long term clinical outcomes in diabetic and nondiabetic patients with acute myocardial infarction undergoing primary angioplasty

Background: Acute myocardial infarction (AMI) patients with type 2 diabetes mellitus are known to present with multiple vessel lesions during coronary angiography. The underlying mechanism remains elusive and there is a shortage of serum prediction markers. In this study, we investigate the relationship between admission HbA(1c) and severity of coronary artery stenosis and subsequent prognosis in AMI patients with or without diabetes. Research design and methods: We measured admission HbA(1c), and vessel scores based on the number of diseased coronary vessels with significant stenosis in 628 patients diagnosed with AMI. Simple and multi-regression analysis were performed to investigate the correlation between HbA(1c) and the severity of coronary artery stenosis. Major adverse cardiovascular events (MACE), including new-onset myocardial infarction, acute heart failure and cardiac death, were documented during the follow-up. 272 non-DM participants and 137 DM participants were separated into two groups based on HbA(1c) levels for survival analysis during a 2-year follow up. Results: 448 non-DM patients and 180 DM patients were included in the initial observational analysis. 272 non-DM patients and 137 DM patients were included in the follow-up survival analysis. The admission HbA(1c) level was found to be significantly positively correlated to the number of affected vessels suffering from significant coronary artery stenosis both in DM (R square = 0.012; 95% CI 0.002 to 0.623, P = 0.049) and non DM patients (R square = 0.025; 95% CI 0.009 to 0.289, P = 0.037). Kaplan-Meier survival analysis revealed no significant difference with regard to different HbA(1c) levels either in DM or non-DM patients at the end of follow-up. Conclusions: In patients with AMI, admission HbA(1c) is an important predictor for the severity of coronary artery stenosis in non-DM and DM patients. Further studies are needed to determine whether longer term follow-up could further identify the prognosis effect of HbA(1c) on MACE.