Clinical Characteristics in Swedish Children With and Without Autoantibodies at the Time of Type 1 Diabetes Diagnosis

OBJECTIVE Autoantibodies have long been recognized as biomarkers of islet autoimmunity in type 1 diabetes, but their role in the pathogenesis is not fully understood. The aim of this study was to analyze clinical and hereditary characteristics of children presenting with and without autoantibodies at type 1 diabetes diagnosis. RESEARCH DESIGN AND METHODS Data were collected from children (<18 years) at the time of diabetes diagnosis as part of Sweden's national Better Diabetes Diagnosis study. Participants were categorized based on the presence or absence of autoantibodies. Variables compared were age at diagnosis, sex, HbA1c, diabetic ketoacidosis (DKA), parental heredity of type 1 and type 2 diabetes, level of C-peptide, BMI SD score (SDS), and HLA genotype. We used t tests, χ2 tests, and logistic regression for comparisons. RESULTS Of the 2,753, children, 169 (6.1%) were autoantibody-negative at type 1 diabetes diagnosis. Of those, 66% were boys compared with 56% of children with autoantibodies (P = 0.009). Also, children without autoantibodies had higher HbA1c at diagnosis (11.3 vs. 10.8% [100 vs. 94 mmol/mol], P = 0.003), were less likely to present with DKA (9 vs. 15%, P = 0.039), and more likely to have parental history of type 2 diabetes (8 vs. 2%, P < 0.001) compared with children with autoantibodies. We did not observe differences for age at diagnosis, C-peptide levels, BMI-SDS, or HLA genotype between the children with and without autoantibodies. CONCLUSIONS We identified differences in clinical characteristics when comparing children with and without autoantibodies at type 1 diabetes diagnosis, highlighting potential heterogeneity in the disease's pathogenesis across subgroups.