Prolonged remission in latent autoimmune diabetes of adults (LADA): Is insulin resistance a major influence?

INTRODUCTION: Type 1 diabetes mellitus (T1DM) is a chronic inflammatory disease that courses with high serum glucose levels as a result of pancreatic beta cell destruction and subsequent insulinopenia. LADA is a type of autoimmune diabetes where damage to the beta cell occurs much slower. The natural history of type 1 diabetes is very heterogeneous and variable. This is especially true for LADA with several possible different clinical courses due to a wider variety of pancreatic cell destruction and insulin resistance. Clinically overt diabetes ensues when more than 80% of pancreatic cell mass is loss. After treatment initiation partial disease remission is common, especially in children. However complete remission is rare, and remission lasting for over a year is even rarer, with few reports published in literature. Some agents such as vitamin D and DPP4 inhibitors have been presented has having potential immunomodulatory effects. CLINICAL CASE: A 36-year-old man with grade 1 obesity (BMI 33 kg/m2) presented at the emergency department with symptoms of insulinopenia (polyuria and polydipsia in the previous 3 months) and hyperglycemia (capillary blood glucose >500mg/dL). Ketonemia was negative and pH was normal on blood gas analysis The diagnosis of diabetes mellitus was made and insulin therapy was instituted on a basal-bolus regimen. At the first follow-up appointment, due to his morphotype and familiar history of type 2 diabetes (mother diagnosed at 52 years of age), he stopped short-acting insulin and was started on metformin and SGLT2 inhibitor. A week later he was admitted in the hospital in euglycemic ketoacidosis. Initial workup revealed positive anti-GAD 41.8 U/mL, HbA1C 9.8%, C-peptide 1.83 ng/mL, serum insuline 17.4 uU/mL. Consequently, metformin and SGLT2 inhibitor therapy was stopped, and the patient resumed basal bolus insulin regimen. He then remained under a basal insulin without need of meal-time insulin bolus, progressively lowering the basal insulin dose until suspension four months later. Simultaneously, lifestyle changes were implemented with significant weigh loss (BMI 33 > 26.4 kg/m2 at the time of insulin suspension). After 3 years of follow-up the patient remains without need of antidiabetic therapy, with normal Hba1c 5.3%. Anti-GAD antibodies remain positive (39.4 U/mL) but C-peptide and serum insulin are within the reference range (1.69 ng/mL [1.1–4–4], 6.9uU/mL [2.6–25], respectively). CONCLUSION: Prolonged disease remission in type 1 diabetes is rare. This case highlights an especially long “honeymoon” period in a patient with LADA. Obesity and insulin resistance probably played a role in the initial patient presentation, and its improvement probably helps to justify this prolonged remission. In spite of the family history of diabetes, other types of diabetes seem unlikely due to positive antibodies and SGLT2 inhibitor associated euglycemic ketoacidosis.