Table 1 shows the diagnostic criteria for acute-onset type 1 diabetes
mellitus (2012). As previously reported diagnostic criteria
for fulminant type 1 diabetes3, it was taken as the 2012 version
because of the possibility of revision. In order to establish the
diagnostic criteria for ‘typical acute-onset type 1 diabetes’,
which can be used easily by general practitioners and can be
adapted to long-standing patients, we selected the following
three conditions as criteria: (i) acute-onset type; (ii) the need
for continuous insulin therapy; and (iii) anti-islet autoantibody
status. Patients are diagnosed as having ‘acute-onset type 1 diabetes
mellitus (autoimmune)’ if they are positive for anti-islet
autoantibodies, whereas they are diagnosed simply as having
‘acute-onset type 1 diabetes mellitus’ if their endogenous insulin
secretion is exhausted without verifiable anti-islet autoantibodies.
However, reassessment is required after certain periods in
case the statuses of anti-islet autoantibodies and/or endogenous
insulin secretory capacity are unknown. Although patients are
diagnosed as having ‘acute-onset type 1 diabetes mellitus (idiopathic)’
if they are negative for autoantibodies to glutamic acid
decarboxylase (GADA), insulinoma-associated antigen 2 (IA-
2A), insulin (IAA) and zinc transporter-8 (ZnT8A) at the onset
of diabetes, this category was not included in the present diagnostic
criteria, because it is difficult to measure all of these autoantibodies
at the clinic. Based on the previous reports, the
prevalence of acute-onset type 1 diabetes (idiopathic) is estimated
to be