A classification of diabetes and other categories of glucose intolerance, based on contemporary knowledge of this heterogeneous syndrome, was developed by an international workgroup sponsored by the National Diabetes Data Group of the NIH. This classification, and revised criteria for the diagnosis of diabetes, were reviewed by the professional members of the American Diabetes Association, and similar versions were circulated by the British Diabetic Association, the Australian Diabetes Society, and the European Association for the Study of Diabetes. The ADA has endorsed the proposals of the international workgroup, and the Expert Committee on Diabetes of the World Health Organization has accepted its substantive recommendations. It is proposed that this classification be used as a uniform framework in which to conduct clinical and epidemiologie research so that more meaningful and comparative data will be obtained on the scope and impact of the various forms of diabetes and other classes of glucose intolerance.
Medical treatment of diabetes is not considered in this paper, and the classification is not an attempt to define guidelines for therapy of patients.
The salient changes proposed in the classification are that 1. The insulin-dependent, ketosis-prone type of diabetes, which is associated with increased or decreased frequency of certain histocompatibility antigens (HLA) on chromosome 6 and with islet cell antibodies, be considered a distinct subclass of diabetes [insulin-dependent diabetes mellitus (IDDM)]. This type of diabetes has been inappropriately termed juvenile diabetes. Since it can occur at any age, it is recommended that diagnosis based on age of onset be eliminated.
2. The noninsulin-dependent, nonketosis-prone types of diabetes, which are not secondary to other diseases or conditions, be considered a second distinct subclass of diabetes [noninsulin-dependent diabetes mellitus (NIDDM)]. This subclass has been divided-according to whether or not obesity is present (obese NIDDM and nonobese NIDDM, respectively), and patients in this subclass can be further characterized by the type of treatment they receive (insulin, oral hypoglycemie agents, diet) or by other characteristics of interest to the researcher. It is believed that heterogeneity within this subclass, and also within IDDM, will be demonstrated by further research.
3. The types of diabetes caused by other conditions or found in increased frequency with other conditions (implying an etiologie relationship) be considered a third subclass of diabetes mellitus—diabetes associated with certain conditions and syndromes. This subclass has been divided according to the known or suspected etiologie relationships.
4. The class gestational diabetes be restricted to women in whom glucose intolerance develops or is discovered during pregnancy.
5. Individuals with plasma glucose (PG) levels intermediate between those considered normal and those considered diabetic [see (8)] be termed to have impaired glucose tolerance. It is proposed that the terms chemical, latent, borderline, subclinical, and asymptomatic diabetes, which have been applied to persons in this class, be abandoned, since use of the term diabetes invokes social, psychologic, and economic sanctions that are unjustified in light of the lack of severity of their glucose intolerance.