GCG and diabetes mellitus: According to the 2012 revised criteria of the Japan Diabetes Society (113), a diagnosis of fulminant DM is confirmed when all of the following three findings are present: (1) rapid occurrence of diabetic ketosis or DKA (~7 days) after the onset of hyperglycemic symptoms, (2) plasma glucose ≥ 288 mg/dL and HbA1c < 8.5% at the first visit, and (3) urinary C-peptide excretion <10 μg/day or fasting serum C-peptide level <0.3 ng/mL and serum C-peptide <0.5 ng/mL after intravenous glucagon administration (or after a meal) at onset.