The original schema for classifying diabetes mellitus (DM) consisted of 2 categories known as type 1 diabetes mellitus and type 2 diabetes mellitus. Type 1 diabetes was also known as insulin-dependent diabetes. Patients with this type of diabetes were considered prone to develop diabetic ketoacidosis (DKA).
Patients with type 1 diabetes were found to have an absolute insulin deficiency due to autoimmune destruction of pancreatic beta cells. Patients with type 2 diabetics, or noninsulin-dependent diabetes, were not considered to be at risk for DKA. Type 2 diabetes is strongly associated with obesity and a family history of diabetes. These patients have peripheral insulin resistance with initially normal or elevated circulating levels of endogenous insulin.