Polyautoimmunity in adults and children with type 1 diabetes mellitus: findings from a Saudi cohort.

Background: Patients diagnosed with type 1 diabetes mellitus (T1DM) have an increased risk of developing other autoimmune disorders, which may complicate the natural history and management of these patients, however, data are scarce from T1DM patients in Saudi Arabia.

Objectives: The aim of this study was to determine the prevalence of autoimmune disorders in T1DM patients as well as to compare metabolic parameters such as glycemic control, anemia, and vitamin D status in those with and without celiac disease (CD).

Methods: This was a retrospective study that was conducted on patients with T1DM receiving care at King Fahad Medical City (KFMC). Data were gathered from medical records on additional autoimmune disorders , including autoimmune markers for thyroid disease, CD, and other laboratory findings such as hemoglobin (Hb), vitamin D, parathyroid hormone (PTH), and glycated hemoglobin (HbA1c).

Results: The study included 322 T1DM patients, with a mean age of 17.4 ± 7.35 years and 55.6% were female. Mean diabetes duration was 10.0 ± 4.9 years. At least one autoimmune disease was identified in 36.9% of T1DM patients. Among the cohort, 22.7% had CD, and 12.4% had autoimmune Hashimoto's thyroiditis (HT), making these as the most predominant autoimmune conditions in this cohort. Additionally, 18.3% of family members of patients with T1DM also had T1DM. No significant differences were found in HbA1c, TSH, and diabetes duration between patients with or without CD. However, CD patients had lower serum free thyroxine (FT4) and Hb levels and exhibited lower serum ferritin. However, serum PTH and vitamin D levels were similar across both groups.

Conclusion: This study highlights a significant prevalence of autoimmune disorders, particularly CD and HT, among this Saudi patients with T1DM. Further research could explore potential links between HLA types and autoimmune disease susceptibility in individuals with T1DM.