1143-P: ZnT8 Autoantibody Positivity Does Not Predict Pediatric Diabetes Presentation or Subsequent Clinical Course

Introduction: Type 1 diabetes specific autoantibodies are glutamic acid decarboxylase (GAD65), protein tyrosine phosphatase-like islet antigen 2 (IA2), insulin (IAA), and Zinc transporter 8 protein (ZnT8). The aim of our study was to determine if the presence of ZnT8 antibodies(Ab) was predictive of clinical presentation at diagnosis or subsequent disease course.

Methods: Between January 2003 and May 2019, 105 patients aged ≤ 21 years with a clinical diagnosis of T1DM had at least 1 diabetes autoantibody measured. For subjects who had less than 4 autoantibodies analyzed initially, residual serum sample was retrieved, and remaining autoantibodies were analyzed. Retrospective chart review was completed. At diagnosis, we evaluated BMI z-score, HbA1c, and the presence and severity of DKA. Complications recorded post diagnosis included episodes of DKA, diagnosis of autoimmune (AI) disease, and the presence of vascular complications.

Results: Of the 105 patients, 71 were ZnT8(+) (68%). When comparing ZnT8Ab(+) to (-) patients at diagnosis, there was no difference in age (p=0.94), BMI z-score (p=0.83) or presence of DKA (p=0.26). There was no difference in duration of follow up between ZnT8 Ab (+) and (-) groups (p=0.54). Over follow-up, (0.05-15.7 years), there was no difference in rates of DKA episodes (p=0.71). There were no macrovascular complications recorded and no difference in microvascular complications between the 2 groups (p=0.14). There were more AI conditions in the ZnT8Ab(+) group, 77% compared to 23% in ZnT8Ab(-), but this did not reach statistical significance (p=0.12).

Conclusions: Our study, unlike others, suggests that the presence of ZnT8 Ab does not result in a difference in disease course at presentation. This study adds to the literature as it has follow up on patients. Over up to 15 years of follow-up, there is no difference in complications between those with and without ZnT8 Ab’s. This study should be validated with larger numbers and longer follow up.