It is not diabetes itself that affects diabetes, but the control of diabetes. There are many treatments available for diabetes, and if a person with diabetes has good glycemic control, it has essentially no effect on life expectancy. Research statistics have found that the average life expectancy of people with type 2 diabetes is lower than that of the general population, but there is also a wide variation in life expectancy among people with type 2 diabetes. For a 40-year-old diabetic patient, the key to how long he or she can live is the control of blood sugar. Some patients diagnosed with diabetes have good glycemic control and exhibit only minor complications, or even no complications, which usually does not affect later life expectancy. However, if the long-term blood glucose control is poor, as the disease progresses, complications of internal organs, peripheral nerves, feet and eyes will gradually appear, and the quality of life will be seriously affected, and the corresponding survival period will be shortened. If complications of diabetic ketoacidosis are not treated in time, death may occur quickly. In conclusion, diabetic patients should have basic knowledge related to diabetes, follow medical advice, adhere to medication, control diet, and closely monitor blood glucose to control blood glucose to within the normal range, so as to reduce complications and prolong survival.