Analysis of the clinical characteristics of insulin autoimmune syndrome induced by alpha-lipoic acid

What is known and objective Alpha-lipoic acid (ALA) is widely used as a dietary supplement and antiageing agent. Insulin autoimmune syndrome (IAS) is the most serious adverse reaction reported with the use of ALA. The purpose of this study was to explore the clinical characteristics of ALA-induced IAS and provide a scientific reference for clinical diagnosis, treatment and prevention. Methods We collected literature on IAS cases induced by ALA for retrospective analysis in Chinese and English. Results and discussion The median age of 37 patients (28 females and 9 males) was 61 years (range 32-82). The symptoms occurred at night and in the early morning (60.7%), in the late postprandial period (50.0%) or after fasting (35.7%), within hours in some patients and up to 2 months in others after stopping ALA or during medication treatment. Autonomic nervous system symptoms (81.1%) and neurological hypoglycaemia (64.9%) are the main clinical manifestations of hypoglycaemia. The blood glucose concentration at the onset of hypoglycaemia was 2.19 mmol/L (median, range 1.09-3.52), the insulin concentration was >= 100 mu IU/ml (94.6%), and the C-peptide concentration was <= 20 ng/ml (83.3%). Testing for IgG insulin autoantibodies (IAAs) was positive in 37 patients. Pancreatic imaging was unremarkable on computed tomography (CT), magnetic resonance imaging (MRI) and abdominal sonography. Hypoglycaemia disappeared within 5 days to 8 months after withdrawing ALA alone or using corticosteroid treatment. IAA turned negative in 7 months (median; range 2-36). Follow-up showed no recurrent hypoglycaemic episodes at 7.25 months (median; range 1-36). What is new and conclusion ALA-induced IAS is a clinically rare autoimmune disease with hypoglycaemia that occurs during medication treatment or after drug withdrawal that should be treated promptly.