Some patients develop endocrine pancreatic insufficiency after pancreatic resection, consisting in impaired carbohydrate metabolism up to diabetes mellitus. Diabetes after  pancreatic resection depends on loss of Langerhans islets and deficiency in the production of insulin.

After partial pancreatic resection, it is common to experience a temporary impairment of carbohydrate metabolism, especially in those patients who receive parenteral nutrition. This condition can be resolved with an adequate diet and a mild antidiabetic therapy. If diabetes develops, insulin is needed to control hyperglycemia and prevent long-term complications. Insulin is given subcutaneously using pre-filled pens. In some patients, diabetes may develop several years after the resection, and depends on chronic obstructive pancreatitis of the remnant.   

The relationship between partial pancreatic resections and diabetes mellitus is still unclear. Patients undergoing left pancreatectomy seem to be at greater risk of developing some form of diabetes in the long term, because the bulk of Langerhans islets is naturally located in the pancreatic tail. 

Total pancreatectomy results in a complete loss of pancreatic endocrine function, with full-manifestations of pancreoprival diabetes. The absence of both insulin and glucagon (that oppose one another) increases the risk for hyperglycemia and hypoglycemia. Significan glycemic fluctuations may occur, with marked post-prandial hyperglycemia and sudden hypoglycemia after insulin administration or during prolonged fasting. Therefore, it is important to provide a diabetes treatment plan that includes frequent blood sugar monitoring and flexible insulin therapy to help decrease the risk of high and low blood sugar.