Abstract
Type 1 diabetes is diagnosed when the patient's endogenous insulin secretion decreases to a level which results in hyperglycemia. After diagnosis, insulin secretion continues to decline. As a reference for clinical trials trying to preserve endogenous beta-cell function in patients with recently diagnosed type 1 diabetes, in this short review I attempt to summarize the natural history of endogenous beta-cell function after the diagnosis of type 1 diabetes.