SAT-618 Preserved C-peptide Five Years After LADA Diagnosis: Focus On Prandial Glycaemic Control

Abstract Disclosure: Y.C. Kon: None. C. Seow: None. Introduction: Latent autoimmune diabetes of adults (LADA), a subtype of DM1, by convention does not require insulin within the first 6-12 months of diagnosis; C-peptide levels decrease more slowly than in DM1. Unlike “need for insulin” which may be clinician dependent, GADA is a key marker (Ss 85-90% Sp ∼ 100%) for LADA diagnosis. Moreover, high titre GADA (≥ 180 U/ml) predicts faster disease progression whereby fasting C-peptide levels fall < 0.6 ng/ml, 200 pM). Low C-peptide and high GADA levels at diagnosis also predict progression to insulin dependency. Similarly, adult DM1 patients with high GADA levels > 41 U/ml at diagnosis are at higher risk of β-cell failure after 5 years. Recent guidelines recommend use of MDI insulin regimen for LADA patients when fasting C-peptide is < 300 pM, as in DM1. We report a female with LADA and GADA > 2000 U/ml treated early with prandial insulin analogue, DPP4-inhibitor but no or minimal doses of basal insulin. Over 5 years, she maintained good glycaemic control with fasting C-peptide > 300 pM. CASE REPORT A 50-year-old Chinese female presented in 2/2020 with 7 kg weight loss since 10/2019, from 65 kg to 58 kg. Her fasting plasma glucose was 15.1 mM, HbA1c 11.9%. OGTT BGL was 13.3 mM (0 min), 31.3 mM (120 min). Thyroid function was normal. She was initially treated with PO metformin 500 mg bid and empagliflozin 12.5 mg om. When first seen by endocrinologist on 4/11/2020, HbA1c had improved to 6.5%, but she had not gained weight (height 161cm, weight 50 kg, BMI 19.2 kg/m2). GADA levels were markedly elevated at > 2000 U/ml. Thus, she fulfilled criteria for LADA. She was started on sc Novorapid 3-6 units 15 mins premeal at 1 unit to 10-gram carbs, and PO linagliptin 5 mg om. Empagliflozin and metformin were discontinued. She was taught to count carbohydrates and avoid high bedtime BGL which resulted in nocturnal overspill glycemia. Her fasting C-peptide improved from 193 pM after diagnosis, and despite persistently high GADA > 2000 U/ml, has remained > 300 pM. Serial CGM showed good control (TIR 3.9-10 mM > 86%). 9/2023 repeat OGTT showed BGL 0 min 7.7 mM, 120 min 20.3 mM. In 3/2024, she was started on insulin pump for FBGL persistently > 7 mM (basal rate 0.15 units/hr; ICR 1:10; ISF 1:3; target BG range 4.5-6mM). Discussion: Within LADA, when C-peptide is < 300 pM, a multiple insulin regimen is recommended, as for DM1. In our case, as informed by serial CGM profiles, we employed early prandial insulin and DPP4-inhibitor therapy without basal insulins. Omitting overnight exogenous basal insulin when β-cell function is still robust (C-peptide > 300 pM) and FBGL ≤ 6.5 mM avoids risk of nocturnal hypoglycemia. Whether her overall stable control is due to natural history or MDI therapy is uncertain. However, the use of DPP4-inhibitors has been found useful. Conclusion: RCTs utilizing C-peptide and CGM to inform the best regimens of insulin and/or OHA treatment for C-peptide preservation in LADA patients are needed. Presentation: Saturday, July 12, 2025