Background: Insulin Autoimmune Syndrome (IAS) is a rare condition characterized by the
combination of recurrent severely spontaneous hypoglycemia without evidence of exogenous insulin
administration, high concentration of total serum insulin, and the presence of a high titer of insulin
autoantibody (IAA). But now we describe a case with IAS caused by gliclazide and hardly occuring
Case Report: A 70-year-old man with type 2 diabetes presented to our department with poor glycemic
control without evidence of hypoglycemia, but the levels of serum insulin and IAA were very high. He
had no exogenous insulin administration history. Switching antidiabetic therapy from gliclazide to
acarbose and metformin, the patient’s serum insulin level and IAA decreased gradually. Accordingly, the
glycemic control improved and there was no episode of hypoglycemia.
Conclusion: Hence, clinicians should pay more attention to type 2 diabetic patients treated with gliclazide
and detect their serum insulin concentration and IAA to exclude or diagnose IAS and perform the best
therapeutic regimen to these patients.