Atopic Dermatitis Associated With Increased Risk of IBD

Joel Gelfand, MD, MSCE

Credit: Penn Medicine

Children and adults with atopic dermatitis (AD) may be at an increased risk of inflammatory bowel disease (IBD), according to new research.¹

A chronic condition in which a disordered immune system causes inflammation that damages the skin barrier, AD is the most common type of eczema and affects 223 million people worldwide.² Skin disorders like AD are common among patients with IBD, with such conditions affecting up to 20% of people with IBD.³

“Studies that examine the association between AD and IBD are important because they shed light on common pathophysiologic mechanisms and because, with the advent of targeted therapeutic approaches, they could influence treatment selection,” wrote investigators.¹

To assess the correlation between AD and IBD, a team of investigators led by Joel Gelfand, MD, MSCE, vice chair of clinical research and medical director in the Dermatology Clinical Studies Unit at Penn Medicine, collected data for more than 5,500,000 patients from January 1, 1994, to February 28, 2015 from The Health Improvement Network, an electronic medical record database. The presence of at least 1 of 5 common diagnostic codes for AD and 2 AD-related treatment codes were used to classify patients as having AD. Participants were stratified into pediatric or adult cohorts based on age at baseline.¹

Using the 5,522,431 within the Health Improvement Network database, investigators matched patients with AD with up to 5 controls based on age, practice, and index date. Of note, investigators used treatment exposure as a proxy for AD severity.¹

For the pediatric population, 1,809,029 pediatric controls were matched with 409,431 children with AD. Among children with AD, 93.2% had disease activity classified as mild, 5.5% were classified as moderate, and 1.3% were classified as severe.¹

For the adult population, 2,678,888 adult controls were matched to 625,083 adults with AD. Among adults with AD, 65.7% had disease activity classified as mild, 31.4% were classified as moderate, and 2.9% were classified severe.¹

Using this data, investigators performed logistic regression to examine the risk for IBD, ulcerative colitis (UC) and Crohn disease (CD) in children and adults with AD compared with controls. Patients with a history of IBD, CD, or UC at cohort entry were excluded from the study. Covariates of interest were age, sex, Townsend index, history of asthma or allergic rhinitis, use of systemic steroids, body mass index (kg/m2), smoking, and alcohol use.¹

In fully adjusted models, the pediatric group had a 44% increased risk of IBD (hazard ratio [HR], 1.44; 95% confidence interval [CI], 1.31-1.58) and a 74% increased risk of CD (HR, 1.74; 95% CI, 1.54-1.97), which increased with AD severity. Of note, patients with AD in the pediatric group did not have an increased risk of UC (HR, 1.09; 95% CI, 0.94-1.27) except for those with severe AD (HR, 1.65; 95% CI, 1.02-2.67). Adults with AD had a 34% (HR, 1.34; 95% CI, 1.27-1.40) increased risk of IBD, a 36% (HR, 1.36; 95% CI, 1.26-1.47) increased risk of CB, and a 32% (HR, 1.32; 95% CI, 1.24-1.41) increased risk of UC, with risk increasing with worsening AD.¹

“This cohort study found an increased risk of IBD and CD in adults and children with AD and an increased risk of UC among all adults with AD and children with severe AD. The finding that this risk increases with worsening severity of AD suggests a possible causal association. Future studies in more diverse populations are needed to help substantiate the validity of our findings,” concluded investigators.¹

References

1. Chiesa Fuxench ZC, Wan J, Wang S, et al. Risk of Inflammatory Bowel Disease in Patients With Atopic Dermatitis. JAMA Dermatol. Published online August 30, 2023. Accessed August 31, 2023. doi:10.1001/jamadermatol.2023.2875
2. Global Atopic Dermatitis Atlas. Global Report on Atopic Dermatitis 2022. Accessed August 31, 2023. https://www.eczemacouncil.org/assets/docs/global-report-on-atopic-dermatitis-2022.pdf
3. Crohn’s and Colitis Foundation. Skin Complications. News from the IBD Help Center. Accessed August 31, 2023. https://www.crohnscolitisfoundation.org/sites/default/files/legacy/assets/pdfs/skin.pdf