1. Impaired insulin secretion (insulin deficiency): Patients with type 1 diabetes have a complete lack of insulin production and secretion. This impairment of insulin secretion (more than 90% of insulin-producing beta cells are permanently damaged) is due to the destruction of beta cells in the pancreas by damage to their immune system. For this reason, type 1 diabetes is also known as an autoimmune disease. As insulin production by the beta cells decreases, the body begins to use fat and muscle tissue. This process can lead to a very dangerous state called ketoacidosis, where ketone bodies and other acidic by-products begin to accumulate in the blood. This state can lead to coma and death. Wang Shenglong, Department of Endocrinology, Anyang Second People’s Hospital Type 2 diabetes is a relative lack of insulin. Although the pancreas is still making insulin, the insulin production is not sufficient to control blood glucose levels. beta cell function in type 2 diabetic patients gradually declines over time. Before a patient’s blood glucose begins to rise, 50-75% of the cell’s insulin-secreting capacity may have been lost. Over time, most patients with type 2 diabetes convert from a relative insulin deficiency to a more severe insulin deficiency. Therefore, most patients with type 2 diabetes require intensive treatment, including daily insulin injections, to ensure that blood glucose levels are under control. Insulin resistance: In insulin resistance, pancreatic beta cells continue to produce insulin at various rates, but the body is unable to use insulin effectively. Insulin resistance is accompanied by many other medical problems seen in patients with type 2 diabetes. The chronic hyperglycemia of type 2 diabetic patients further deteriorates beta cell function, and over time, type 2 diabetes progresses to relative insulin deficiency. Although beta-cell dysfunction is the main problem in diabetes, in some cases this impairment can be reversed and, therefore, insulin secretion may be restored by lowering blood glucose levels. This effect is more likely to occur early in the disease. In the past, type 2 diabetes was referred to as adult-onset non-insulin-dependent diabetes mellitus. This does not describe the disease well, as we know that insulin therapy may be the best way to control blood glucose in many patients during insulin deficiency.