424-P: Autoantibodies to Glutamic Acid Decarboxylase in Type 1 Diabetes Are Not a Marker of Asymptomatic Cardiac Autonomic Neuropathy

Aim: To clarify whether autoantibodies against glutamic acid decarboxylase (GAD-ab) are associated with cardiac autonomic neuropathy (CAN). Methods: 319 consecutive patients with type 1 diabetes (DM1) were included. We assessed CAN by responses of heart rate variability to deep breathing (E/I index), Valsalva maneuver, standing (30:15 ratio), low-frequency activity (LFa), and high-frequency activity (HFa). We assayed GAD-ab by immunoprecipitation radioligand. Results: Mean age was of 40 ± 14 years, with 20 ± 12 years as mean duration of diabetes. Mean A1c was 7.2 ± 1.0%. We confirmed CAN in 66 patients resulting in a 21% (95% CI 17-25) prevalence of asymptomatic CAN. GAD-ab were present in 199 individuals (62%), with no significant differences as a function of the presence of CAN or not [44 (70%) vs. 144 (66%), respectively; P = 0.544]. GAD-ab titles were similar between both groups (431 ± 695 U/mL in CAN subjects vs. 390 ± 662 U/mL in subjects without CAN, P = 0.688). Considering all patients as a whole, GAD-ab titles only correlated with duration of DM1 (r = -0.346, P Conclusion: GAD-ab unlikely have a role as a CAN marker in patients with DM1. Disclosure L. Nattero-chavez: None. E. Lecumberri: None. H. F. Escobar-morreale: Consultant; Self; InsudPharma. M. Luque-ramirez: None. J. Quinones silva: None. L. Montanez: None. E. Fernandez duran: None. B. Dorado avendano: None. C. Sanchez rodriguez: None. M. Lorenzo: None. M. Fernandez argueso: None. N. Bengoa rojano: None. Funding Menarini International Foundation