Diabetes is divided into 4 different classes:
1) Type 1 diabetes (results from beta-cell destruction, usually leading to absolute insulin deficiency)
2) Type 2 diabetes (results from a progressive insulin secretory defect on the background of insulin resistance)
3) Other specific types of diabetes due to other causes, e.g. genetic defects in beta-cell function, genetic defects in insulin action, diseases of the exocrine pancreas (such as cystic fibrosis, pancreatitis) and
drug- or chemical-induced (such as in the treatment of HIV/AIDS or after organ transplantation)
4) Gestational diabetes mellitus (GDM) (diabetes diagnosed for the first time during pregnancy that is not clearly overt diabetes).