A case of type 1 Diabetes mellitus unresponsive to insulin glulisine

A 29-year-old man applied to the internal medicine outpatient clinic with fatigue and high plasma glucose levels. He had type 1 Diabetes Mellitus for 10 years and was using insulin glargine U300 and insulin glulisine for treatment. His glycosylated hemoglobin level was 16.7%, and he was hospitalized. Insulin doses were calculated as 1 unite/kg /day; glulisine 3x8 unit/day and glargine U300 1x18 unit/day were ordered. Although we increased the total insulin dosage to 1,5 units/kg/day, the plasma glucose measurements did not improve. The short-acting insulin analog was switched to insulin aspart based on the fact that insulin autoantibodies might cause this situation. On aspart treatment, the patient suffered from hypoglycemia with the same doses of glulisine. The occurrence of insulin autoantibodies against glulisine was confirmed clinically. Basal insulin dose was reduced to 20 units, and aspart 3x6 units/day was enough for plasma glucose control.  Hyperglycemia due to autoantibodies against analog insulins is very rare. Here we report a type 1 Diabetes Mellitus patient who was on glulisine treatment for 10 years, and whose blood glucose measurements deteriorated recently. Hyperglycemia was regulated after the insulin switch from glulisine to aspart. This rare case report must be kept in mind in hyperglycemic patients with a history of long-time analog insulin treatment.