Late-onset autoimmune diabetes in 2 octogenarians: diagnostic misclassification and therapeutic heterogeneity

Latent autoimmune diabetes in adults (LADA) may be misclassified as type 2 diabetes mellitus (T2DM) and remain unrecognized without targeted evaluation. We describe 2 octogenarians with LADA initially managed as T2DM. The first, an 84-year-old man with chronic kidney disease and normal body mass index, developed glycemic variability with hypoglycemia on multiple daily insulin injections and was intolerant of noninsulin therapies. Evaluation revealed positive pancreatic autoantibodies and preserved C-peptide of 5.68 ng/mL (SI: 1.89 nmol/L) (reference range, 1.1-5.5 ng/mL [SI: 0.37-1.83 nmol/L]). Following transition to automated insulin delivery (AID), time in range (TIR; glucose 70-180 mg/dL [SI: 3.9-10.0 mmol/L]) improved from 33% to 75% and glucose management indicator (GMI) from 8.4% (SI: 68 mmol/mol; targets individualized) to 7.0% (SI: 53 mmol/mol), within 1 month, sustained at 6 months without hypoglycemia. The second, an 80-year-old woman receiving insulin and metformin, developed hypoglycemia; evaluation showed positive pancreatic autoantibodies and preserved C-peptide (1.6 ng/mL [SI: 0.53 nmol/L]). She underwent treatment de-escalation, achieving control on metformin alone with 77% TIR and GMI of 7.0% (SI: 53 mmol/mol) at 1 month, sustained at 3 months without hypoglycemia. These cases highlight preserved endogenous insulin secretion and therapeutic heterogeneity in LADA, requiring individualized management, including AID.