High prevalence of comorbid autoimmune diseases in adults with type 1 diabetes from the HealthFacts database.

ABSTRACT

BACKGROUND: Patients with type 1 diabetes (T1D) are at risk for other autoimmune diseases (ie, polyautoimmunity). The prevalence and risk factors of this phenomenon have been underreported in adults and ethnic minorities, and data are lacking regarding non-endocrine autoimmune diseases. METHODS: Study population data were gathered from HealthFacts, a deidentified patient database compiled from electronic medical records systems in the US. Patients with an International Classification of Diseases diagnosis code specifying T1D were included in the study, whereas those with a diagnosis of type 2 diabetes were excluded. RESULTS: The cross-sectional study cohort comprised 158 865 adults with T1D (mean [±SD] age 51.4 ± 18.9 years, 52.5% female). The most common autoimmune diseases were thyroid disease (20.1%), systemic rheumatic diseases (3.4%), rheumatoid arthritis specifically (2.0%), and gastrointestinal autoimmune diseases (1.4%). Most of the autoimmune diseases were more common in women (eg hypothyroidism, hyperthyroidism, celiac disease, rheumatoid arthritis, lupus, and Sjögren syndrome). Caucasians were more likely than other ethnicities to have an additional autoimmune disease. The prevalence of autoimmune diseases increased with increasing age, significantly in women, such that 38.5% of women over 80 years of age had an additional autoimmune disease, compared with 17.9% of women aged ≤29 years. CONCLUSIONS: Additional autoimmunity represents a significant comorbidity in patients with T1D. Autoimmune diseases are more common in Caucasians and in women, and increase with age. Clinicians treating patients with T1D should be aware of the risk factors for additional autoimmune diseases.