High Prevalence of Comorbid Autoimmune Diseases in Adults with Type 1 Diabetes from the HealthFacts Database.

BACKGROUND: Patients with type 1 diabetes are at risk for other autoimmune diseases (ie. polyautoimmunity). The prevalence and risk factors of this phenomenon has been under-reported in adults and ethnic minorities, and data is lacking about non-endocrine autoimmune diseases.

METHODS: Study population data was gathered from the HealthFacts, a de-identified patient database from electronic medical records systems in the United States. Patients with an International Classification of Diseases diagnosis code specifying type 1 diabetes were included, and patients with a diagnosis of type 2 diabetes mellitus were excluded.

RESULTS: The cross-sectional study cohort comprised 158,865 adults with type 1 diabetes, mean age 51.4 ± 18.9 years and 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 Sjogren's). Caucasians were more likely than other ethnicities to have an additional autoimmune disease. Autoimmune disease prevalence increased with increasing age, significantly in women, such that 38.5% of women over the age of 80 years had an additional autoimmune disease, relative to 17.9% of women age 29 years or younger.

CONCLUSIONS: Additional autoimmunity represents a significant comorbidity in patients with type 1 diabetes. Autoimmune diseases are more common in Caucasians and in women and increase with age. Clinicians treating patients with type 1 diabetes should be aware of the risk factors for additional autoimmune diseases. This article is protected by copyright. All rights reserved.