Relationship among Insulin Therapy, Insulin Resistance, and Severe Coronary Artery Disease in Type 2 Diabetes Mellitus

Objectives.The effect of insulin therapy on coronary artery disease (CAD) remains controversial. This study aimed to analyze the association between insulin resistance and the morbidity of severe CAD in type 2 diabetes mellitus (T2DM). Methods. A total of 2044 T2DM patients aged ≥40 years were included in this cross-sectional observational study. Clinical information and laboratory results were collected from the medical records. Those who underwent percutaneous coronary intervention (PCI) were classified as severe CAD, while those who did not have a history of and were not suffering from CAD were classified as patients without CAD. Results. T2DM patients with severe CAD and without CAD had no significant differences in glycosylated hemoglobin A1c (8.55% ± 2.10% vs. 8.39% ± 1.77%, P=0.234). The proportion of insulin treatment was also similar between the two groups (56.85% vs. 53.65%, odds ratio = 1.138, P=0.310). In the patients without insulin treatment, the levels of fasting C peptide (FCP) correlated with severe CAD prevalence. FCP was categorized into 3 tertiles (