Classification of Diabetes

The classification of diabetes includes four clinical classes Type 1 diabetes (results from β-cell destruction, usually leading to absolute insulin deficiency) Type 2 diabetes (results from a progressive insulin secretory defect on the background of insulin resistance) Other specific types of diabetes due to other causes; e.g., genetic defects in β-cell function, genetic defects in insulin action, diseases of the exocrine pancreas (such as cystic fibrosis), and drug- or chemical-induced diabetes (such as in the treatment of HIV/AIDS or after organ transplantation) Gestational diabetes mellitus (GDM; diabetes diagnosed during pregnancy that is not clearly overt diabetes) Some patients cannot be clearly classified as having type 1 or type 2 diabetes Clinical presentation and disease progression vary considerably in both types of diabetes Occasionally, patients who otherwise have type 2 diabetes may present with ketoacidosis Similarly, patients with type 1 diabetes may have a late onset and slow (but relentless) progression despite having features of autoimmune disease Such difficulties in diagnosis may occur in children, adolescents, and adults The true diagnosis may become more obvious over time5Reference American Diabetes Association. Standards of medical care in diabetes—2013. Diabetes Care 2013;36(suppl 1):S11.