Diabetes is one of the high-risk factors for macrovascular complications. If patients are also combined with hypertension, hyperlipidemia, obesity, smoking, and have a family history of cardiovascular disease, the patient’s risk of developing macrovascular complications will increase significantly. If diabetic patients have poor glycemic control, along with the above-mentioned high-risk factors, the following types of macrovascular complications can occur: 1. cardiovascular, patients can be complicated by coronary artery disease, angina pectoris, myocardial infarction, severe multi-branch lesions of the coronary arteries, patients can have the risk of sudden death. 2. cerebrovascular, patients have a significantly increased risk of multiple stenosis of the cerebral arteries, recurrent cerebral infarction, large cerebral infarction. 3. peripheral blood vascular complications, patients can develop arteriosclerosis and occlusion of the lower extremities, which can lead to dry gangrene in severe cases. If the patient is accompanied by high blood glucose and the presence of incomplete obstruction of blood vessels, this can be accompanied by wet gangrene. If a diabetic patient has lower extremity atherosclerosis, it can lead to a significantly increased risk of amputation.