Non-immune-mediated versus immune-mediated type 1 diabetes: diagnosis and long-term differences-retrospective analysis.

Background: The American Diabetes Association proposed two subcategories for type 1 diabetes mellitus: type 1A or immune-mediated diabetes (IDM) and type 1B or idiopathic diabetes. The absence of β-cell autoimmune markers, permanent insulinopenia and prone to ketoacidosis define the second category, whose pathogenesis remains unclear. Only a minority of patients fall into this category, also designated non-immune-mediated (NIDM), which is considered by several authors similar to type 2 diabetes.