Diagnostic Criteria for Slowly Progressive Insulin-dependent (Type 1) Diabetes Mellitus (SPIDDM) (2012) -Report by the Committee on Slowly Progressive Insulin-dependent (Type 1) Diabetes Mellitus of the Japan Diabetes Society-

Abstract

Diagnostic criteria for slowly progressive insulin-dependent (type 1) diabetes mellitus (SPIDDM) have been proposed by the Committee on Slowly Progressive Insulin-dependent (Type 1) Diabetes Mellitus of the Japan Diabetes Society. The following two criteria are required for a definitive diagnosis: 1) the presence of glutamic acid decarboxylase antibodies (GADAbs) and/or islet cell antibodies (ICAs) at some time during the patient's clinical course and 2) the absence of ketosis or ketoacidosis at the onset (or diagnosis) of diabetes mellitus without the need for insulin treatment to correct hyperglycemia immediately after diagnosis. It remains unclear whether insulinoma-associated antigen-2 autoantibodies (IA-2Abs), insulin autoantibodies (IAAs) or zinc transporter 8 autoantibodies (ZnT8Abs) are essential markers for the diagnosis of SPIDDM. Hence, the presence of IA-2Abs, IAAs and ZnT8Abs was excluded from the diagnostic criteria for SPIDDM. Furthermore, ketosis and/or ketoacidosis are observed in cases of SPIDDM complicated by soft drink-induced ketosis. Supplementary information for the diagnosis includes the following: 1) most SPIDDM patients require insulin treatment for more than three months after the onset (or diagnosis) of diabetes mellitus and frequently progress to an insulin-dependent state, 2) GADAbs and ICAs become negative during the clinical course in many cases, 3) a small proportion of patients will maintain their endogenous beta cell function, irrespective of the titer of GADAbs and ICAs, over 10 years after the onset (or diagnosis) of diabetes; and 4) sometimes, early insulin treatment is initiated when GADAbs and/or ICAs are positive in both adult and pediatric cases.