RBP4 and type 2 diabetes mellitus: This study sought to compare the complexity of coronary arterylesions and coronary artery elasticity between patients with CHD combined withT2DM and those with CHD without T2DM, analyze the risk factors affecting coronaryartery elasticity, and investigate the value of RBP4 in assessing coronary arteryelasticity in patients with CHD and T2DM.