I. Identification of Chemical Diabetes

The natural history of diabetes mellitus can be arbitrarily divided into four stages based on the presence or absence of abnormal carbohydrate metabolism. Overt diabetes is the most advanced stage, characterized by elevated fasting blood glucose concentration and classical symptoms. This stage is divided into ketotic and nonketotic forms. Preceding overt diabetes is the latent or chemical diabetic stage, with no symptoms of diabetes but demonstrable abnormality of oral or intravenous glucose tolerance. Subclinical diabetes is an earlier stage when glucose tolerance is abnormal only with stress, such as pregnancy or the administration of cortisone. The earliest stage, prediabetes, extends from conception until the first demonstrable abnormality in glucose tolerance. In groups of presumed prediabetic individuals, delayed and/or decreased plasma insulin response to glucose has been noted. Progression of the diabetes may not occur, may occur very slowly or very rapidly, and regression to an earlier stage of abnormality may also occur.