The changing classification and diagnosis of diabetes

New classification is based on pathogenesis, not insulin dependence

Papers p 371 General practice p 390

At its annual meeting in June 1997 the American Diabetes Association announced the conclusions of an expert committee, which recommended changes to the way that diabetes is classified and to the choice of diagnostic method and cut off value that should be used to define the disease.1 A provisional report from a World Health Organisation consultation group, with some overlap in members with the American committee, has recently been published.2 These recommendations could have important epidemiological implications, but they will also affect individual patients.

The previous classification of diabetes was based on the extent to which a patient was dependent on insulin.3Although this was a logical distinction that separated the two main forms of diabetes, it gave rise to clumsy and sometimes confusing subcategories. Both the reports of the American Diabetes Association and the WHO recommend altering the classification to define four main subtypes of diabetes. Type 1 includes immune mediated and idiopathic forms of β cell dysfunction which lead to absolute insulin deficiency. Type 2 diabetes is disease of adult onset, which may originate from insulin resistance and relative insulin deficiency or from a …