Reclassifying or Declassifying Diabetes? Can Clinical Characteristics Guide Classification and Treatment?

The ultimate demonstration of an immune-mediated cause of diabetes would require documenting an immune infiltrate within islets. In type 1 diabetes, all defects are ultimately secondary to insulin deficiency whereas in type 2 diabetes the relative contribution of these parameters is more variable. Defective and/or delayed insulin secretion is the hallmark of all forms of diabetes and the presence of hyperglycemia implies that the degree of insulin secretion is inadequate for the prevailing insulin action. Both type 1 and type 2 exhibit genetic predisposition to the disease but the environmental contribution to type 2 diabetes is much more prominent. In a cohort of Belgian patients with type 1 diabetes presenting before age 40, 24% did not have autoantibodies. Atypical diabetes or “ketosis-prone type 2 diabetes” were monikers used to describe obese minority patients presenting with diabetic ketoacidosis as their first manifestation of diabetes.