2245-P: Heterogeneity of Adult-Onset Autoimmune Diabetes: Distinct Clinical Phenotypes beyond LADA

Introduction and Objective: Autoimmune diabetes (AD) in adults remains underrecognized. The current ADA classification does not distinguish Latent Autoimmune Diabetes in Adults (LADA) as a separate category but considers it a slowly progressive form of adult-onset type 1 diabetes. LADA is defined as AD diagnosed after age >30 years without insulin dependence during the first 6 months. This study aimed to estimate the frequency of AD in newly diagnosed adults with diabetes (DM) and compared phenotypic characteristics between LADA and AD not meeting LADA criteria (non-LADA AD) Methods: Cross-sectional study, 1,000 adults >30 years with newly diagnosed DM from 12 primary care centers (55.9% men; age 62.8±10.8 years). Clinical, biochemical (including anti-GAD65 and IA-2) and anthropometric data were collected. Participants with pancreatic autoimmunity were classified as LADA or non-LADA AD according to insulin dependence in the first 6 months, and groups were compared using chi-square and Mann-Whitney U tests Results: Overall, 7.6% (n=76) had AD. Among them, 78.9% (n=60) met LADA criteria and 21.1% (n=16) were non-LADA AD. Compared with LADA, non-LADA AD were more often <50 years at diagnosis (50.0% vs 21.7%; p=0.024), lean (BMI≤25 kg/m²: 68.8% vs 25.4%; p=0.013), and less frequently hypertensive (12.5% vs 41.7%; p=0.030). Non-LADA AD showed more hyperglycemic symptoms at onset (87.5% vs 26.7%; p<0.001), higher HbA1c (10.6±2.9% vs 7.8±2.2%; p=0.001), higher HDL-cholesterol (60.1±14 vs 50.3±11 mg/dL; p=0.014), and lower triglycerides (87±37 vs 123.8±62 mg/dL; p=0.024) Conclusion: Nearly 8% newly diagnosed DM had AD, most fulfilling LADA criteria but with a relevant subset presenting a more “classic” type 1-like phenotype. Non-LADA AD patients were younger, thinner, more symptomatic, and had higher HbA1c with a more favorable lipid profile and lower hypertension burden than LADA. These findings underscore the substantial heterogeneity within adult-onset AD and support systematic screening for AD in adults with new-onset DM to improve classification and management Disclosure P. Vich-Pérez: None. M. Salinero-Fort: None. B. Taulero-Escalera: None.