P-113: Prevalence of autoimmune diseases in patients with type 1 diabetes mellitus followed at a tertiary hospital in Brazil
C Andrade Coutinho, G Carvalho Pinho, A C Lins Neves, V Leão de Medeiros, A H de Azevedo FerreiraAbstract
Introduction
Type 1 diabetes mellitus(T1DM) is an autoimmune disease, and individuals with T1DM are at risk of developing other autoimmune diseases(AIDs) such as Hashimoto’s thyroiditis(HT) and celiac disease(CD).
Objectives
To evaluate the prevalence of autoimmune diseases associated with T1DM in a pediatric population from a tertiary center.
Methods
This observational, retrospective, and descriptive study was conducted at tertiary hospital in Brazil, with data collection from March2025 to April2026. Patients diagnosed with T1DM and followed between 2004 and 2026 were included. Data were obtained from medical record. Variables analyzed included anti-thyroglobulin[anti-TG], anti-thyroid peroxidase[anti-TPO], anti-tissue transglutaminase IgA[anti-TTG]), thyroid-stimulating hormone(TSH), free thyroxine(free T4), immunoglobulin A(IgA) and duodenal biopsy results. Screening for HT was performed annually. For CD, screened annually during the first five years after T1DM diagnosis or upon symptom onset. Statistical analysis was performed using Epi Info™, with calculation of frequencies, means, and standard deviations(SD).
Results
Among 213patients, the mean time from T1DM diagnosis to thyroiditis was 5.46years(SD±3.67). The prevalence of HT was 57cases(26,7%); 46were anti-TPO positive and 28anti-TG positive. Thyroid dysfunction occurred in seven patients(six hypothyroidism, one hyperthyroidism). CD screening was recorded in 158patients; one of whom had a prior diagnosis of CD before the diagnosis of type 1 diabetes. Among the remaining, six were anti-TTG positive and five had histological confirmation, resulting in a prevalence of 3.1%. Other AIDs included vitiligo(n=2), alopecia areata(n=1), and systemic lupus erythematosus(n=1).
Conclusions
A considerable prevalence of autoimmune diseases was observed in patients with T1DM, particularly HT and CD. These findings reinforce the importance of regular screening and long-term follow-up, as early diagnosis and treatment may improve clinical outcomes and glycemic control.