Abstract: AIM: To explore the clinical features of insulin autoimmune syndrome (IAS) induced by methimazole in Chinese population. METHODS: The literature on IAS cases caused by methimazole in the Chinese population published before and after June 30, 2019 was collected for retrospective analysis.RESULTS:The age of onset of men was earlier than that of women, and the sex ratio was 1∶2.31 in 95 patients.After taking methimazole 30 mg/d, IAS occurred most from one month to three months,characterized by neuropathic hypoglycemia as the first symptoms at night and early in the morning,blood sugar below 2 mmol/L,insulin concentration≥100 mU/L, IAA positive and no obvious abnormalities in pancreas imaging.The symptoms gradually relieved after symptomatic treatment and stopped taking methimazole. There was no significant difference in the time of hypoglycemia disappearance between the 54 patients who received hormone therapy and non-hormone therapy.CONCLUSION:Methimazole-induced IAS is a clinically rare autoimmune disease. It should be treated promptly occuring hypoglycemia or hyperglycemia during medication.The prognosis of IAS is generally good after proper treatment.

Key words: insulin autoimmune syndrome(IAS), methimazole, insulin autoantibodies(IAA), hypoglycemia