Severe Insulin Resistance secondary to insulin antibodies induced by Insulin Glargine

Background: Medical literature well-documents insulin resistance related to insulin antibodies (IAs), particularly in patients treated with human insulin or insulin analogs. Case report: We report a case involving a 25-year-old female patient with a 7-year history of type 1 diabetes mellitus (DM) who required hospital admission due to a poorly controlled glycemic state (HbA1C 10.0%) despite escalating insulin dosages, reaching four units per kilogram per day before admission and concomitant progressive weight loss. The presence of circulating anti-insulin antibodies was identified upon investigation, leading to severe insulin resistance. The patient responded positively to the replacement of insulin glargine with insulin detemir. Conclusion: This case highlights the importance of recognizing immunological factors, specifically anti-insulin antibodies, as potential contributors to insulin resistance in individuals with type 1 diabetes mellitus.