Atopic Dermatitis Tied to Risk for Autoimmune Disorders

The risk for autoimmune disorders in patients newly diagnosed with atopic dermatitis (AD) is increased compared with the general population, and particularly for people with severe AD, according to findings from a retrospective cohort analysis published as a brief report in The Journal of Allergy and Clinical Immunology.

Investigators obtained demographic and comorbidity data from adults and children in the Oxford-Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) primary care database and identified those with newly diagnosed AD. Investigators matched each AD patient with 4 control patients by age, sex, and time since practice registration. Control patients required at least 1 year of follow-up to solve for possible nonrecorded existing AD diagnosis. Crohn disease, ulcerative colitis, celiac disease, pernicious anemia, type 1 diabetes, autoimmune hypothyroidism,

Graves disease, psoriatic arthritis, rheumatoid arthritis, ankylosing spondylitis, systemic lupus erythematosus, Sjögren syndrome, vitiligo, alopecia areata, and multiple sclerosis were included for analysis. The first recorded diagnosis of a list of common autoimmune disorders for both patient groups was a composite outcome.

Investigators used Cox proportional hazard models stratified by matched sets to estimate unadjusted and adjusted hazard ratios (HRs) representing the association between AD and disease-specific prevalence, composite prevalence, and risk for new-onset autoimmune disease. Investigators used time-dependent Cox models to evaluate the association between AD severity and the composite autoimmune outcome.

There were 173,709 AD patients matched with 694,836 control participants. The mean age for both groups was approximately 27 years, about 53% of both groups were women, and approximately 80% of both groups were White.

At AD diagnosis, patients with AD had a higher prevalence of autoimmune diseases (5.84% [95% CI, 5.73-5.95]) than control participants (4.31% [95% CI, 4.26-4.36]; P <.001). In patients without autoimmune disorders, the incidence of new-onset autoimmune disorder was higher in patients with AD (3.9%) than control participants (2.7%) during a mean follow-up period of 4.1 years. There was an association between AD and new onset of any autoimmune disorder (adjusted HR [aHR], 1.28; P <.001). Increasing AD severity was associated with a greater risk for autoimmune disease (aHR for AD patients vs control participants: 1.99 for severe AD, P <.001; 1.22 for moderate AD, P <.001; 1.22 for mild AD, P <.001). The increased risk for autoimmune diseases in adult patients with AD compared with control participants was consistent across subgroup analyses. In children, increased risk for autoimmune disease was only seen for patients with more severe AD.

Specifically, investigators found increased risk in patients with AD for rheumatoid arthritis and inflammatory bowel disease in patients with AD, for psoriatic arthritis, Sjögren syndrome, vitiligo, alopecia areata, pernicious anemia, and autoimmune hypothyroidism.

“Of note, the prevalence of psoriatic arthritis was the same in cases and controls at AD diagnosis, but we observed a much higher incidence of psoriatic arthritis after diagnosis in cases,” researchers noted although the relationship is unclear.

The study was limited by the lack of verification of physician-coded diagnoses.

“Our study underscores the need for increased clinician awareness of the burden of autoimmune comorbidities in patients with AD, and it highlights a need for expert guidance on screening recommendations in clinical practice,” the study authors wrote.

Disclosure: Several study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.