If blood glucose is elevated and diabetes mellitus is diagnosed, prolonged poor control of blood glucose may lead to a series of complications, such as diabetic cardiovascular complications, diabetic cerebrovascular disease, diabetic nephropathy, diabetic retinopathy, and so on. It is recommended that diabetic patients actively control their blood glucose levels under the guidance of their doctors. 1. Chronic complications of diabetes mellitus have become the main cause of disability and death from diabetes mellitus, including diabetic cardiovascular complications, cerebrovascular disease, retinopathy, etc.. Diabetic cardiovascular complications include cardiac and macrovascular and microangiopathy, cardiomyopathy, cardiac autonomic neuropathy and coronary artery disease. 2. Diabetic ketoacidosis is one of the common acute complications of diabetes. It is a clinical syndrome mainly manifested by hyperglycemia, ketosis, metabolic acidosis and dehydration due to the severe lack of insulin activity and inappropriate elevation of glucagon, which causes disorders of sugar, fat and protein metabolism, resulting in the imbalance of water, electrolyte and acid-base balance. It is recommended that patients with hyperglycemia actively cooperate with doctors to keep their blood glucose within the normal range, monitor their blood glucose regularly, and consult a doctor if they feel unwell, so as to avoid delaying their condition.