Racial/Ethnic Differences in Autoimmune Disease Prevalence in US Claims/EHR Data

OBJECTIVES: Few studies have evaluated racial and ethnic differences in several immune -mediated inflammatory diseases (IMIDs) or overlap syndrome (the co -occurrence of >= 2 IMIDs). We assessed associations between race and ethnicity and prevalence of IMIDs and overlap syndrome using US claims and electronic health records from 2021. STUDY DESIGN: Retrospective cohort study of 10.8 million adults. METHODS: We identified the 10 most prevalent IMIDs among frequently discussed IMIDs. We estimated associations between the 5 most prevalent IMIDs and overlap syndrome in Hispanic and non -Hispanic Asian and Black adults using non -Hispanic White adults as the referent and stratifying by sex and age (20-39, 40-59, and >= 60 years). RESULTS: Inflammatory bowel disease (IBD), systemic lupus erythematosus (SLE), multiple sclerosis (MS), and rheumatoid arthritis (RA) were the most prevalent IMIDs in all races and ethnicities. We observed positive associations (P < .0001) between Hispanic and non -Hispanic Black adults and SLE, Asian women of all ages and Asian men younger than 60 years and SLE, Black women younger than 60 years and MS, and Hispanic and non-White women 60 years or older and RA. Hispanic and non-White adults of all age groups had inverse associations (P < .0001) with IBD. Non -Hispanic Black adults of all ages and Hispanic and non -Hispanic Asian women 40 years or older had inverse associations (P < .0001) with psoriasis/psoriatic arthritis. Overlap syndrome was rare among all groups, with some variation in which IMIDs co-occurred. CONCLUSIONS: We found racial and ethnic differences in the prevalence and co -occurrence of IMIDs in this sample of US adults. Because misdiagnoses are relatively frequent for patients with IMIDs, awareness of racial and ethnic variations in IMIDs could aid early diagnosis and improve disease management.