[Analysis of 4,164 type 1 diabetes antibody profiles in a Chilean health centre].

Background: Previous studies have assessed the role of Type 1 diabetes (DM1) antibodies as predictors of the natural history of disease.

Aim: To determine the frequency and combinations of positivity for DM1 antibodies in patients with DM1 and the relationship between antibody positivity and the age of the patient. To explore the relationship between history of insulin therapy or diabetic ketoacidosis (DKA) at the onset of the disease with antibody positivity in a subsample.

Material And Methods: Data was gathered from every sample processed for DM1 antibodies in our laboratory between January 2015 and September 2019. Medical records from 84 patients who tested positive for at least one antibody were revised to study the relationship between insulin therapy or DKA at the onset of the disease with antibody positivity.

Results: Forty percent of DM1 antibody tests were positive. Among positive tests, 1, 2, 3 or 4 DM1 antibodies were detected in 48%, 33%, 17% and 3% of cases, respectively. The likelihood of testing positive was inversely related with age for ICA, GAD, IA-2, ZnT8 and directlyproportionalforIAA (p= -0,012; -0,013; -0,014; -0,009; 0,005 respectively). An association between DKA at the onset of the disease and IA-2 positivity was observed (Odds ratio (OR) 5.38 95% confidence intervals (CI) 1.79 - 16.16, P < 0.01). No association was found between IAA positivity and history of insulin therapy (OR 2.25 95%CI 0.63 - 7.90, P = 0.2403). The results obtained from this study represent a novel local profile of DM1 antibody data, highlighting a relationship between antibody positivity and age.