Hypoglycemia in diabetes with low-affinity insulin antibody successfully improved by treating sleep apnea syndrome.

Glucose fluctuations, such as hypoglycemia, can cause atherosclerosis in patients with diabetes mellitus. Insulin antibodies with low affinity for insulin rarely cause blood glucose fluctuations, and no established treatment strategy currently exists. A 61-year-old man repeatedly experienced hyperglycemia in the afternoon and hypoglycemia from midnight to early morning. The patient had a history of insulin therapy for 20 years and received hemodialysis. Insulin antibodies with low affinity and high binding capacity were also detected. A positive correlation was observed between blood pH and fasting glucose levels. Sleep apnea syndrome remained untreated with continuous positive airway pressure owing to a deviated nasal septum, which reduced oxygen saturation while sleeping. Glycemic fluctuations improved after otolaryngologic surgery. Modeling of the insulin antibody in this patient suggested that reduced affinity resulted in the release of 8% of insulin from the antibody. Improvement in blood acidosis may help manage early morning hypoglycemia associated with insulin antibodies.