The published recently in JAMA Dermatology.
The study also found an increased risk for Crohn’s disease (CD) in adults and children with AD, as well as an increased risk for ulcerative colitis (UC) in adults with AD and in children with severe AD, researchers reported.
“It is imperative for clinicians to understand atopic dermatitis and the trajectory of our patients with it in order to provide the best standard of care,” senior author Joel M. Gelfand, MD, MSCE, professor in clinical investigation with the department of dermatology at the University of Pennsylvania, Philadelphia, said in a news release.
Courtesy Dr. Gelfand
Dr. Joel M. Gelfand
“There are new and better treatments for AD today, and there will likely continue to be more,” continued Dr. Gelfand. “But providers have to understand how those treatments could impact other autoimmune diseases. For patients with AD and another autoimmune disease, some currently available medications can exacerbate symptoms of their other disease or can help treat two immune diseases at the same time.”
The study results support the idea that AD and IBD may have some common underlying causes, said Sheilagh Maguiness, MD, pediatric dermatologist and associate professor in the department of dermatology at the University of Minnesota, Minneapolis, who was asked to comment on the findings.
“As the pathogenesis of AD is becoming better understood, we are recognizing that, rather than simply a cutaneous disease, the underlying inflammation and immune dysregulation that leads to AD best categorizes it as a systemic inflammatory disease with significant comorbidities,” she told this news organization. “I will be more likely to ask patients and families about GI symptoms, and if positive, may plan to refer to GI more readily than in the past,” added Dr. Maguiness, who was not involved in the study.
Dr. Sheilagh Maguiness
UK general practice cohort
AD has been associated with an increasing number of comorbidities, including IBD, but studies linking AD with IBD, including UC, have had mixed results, the authors wrote. And few studies have separately examined how AD or AD severity may be linked with UC or CD risk.
To examine the risk for new-onset IBD, UC, and CD in children and adults with atopic dermatitis, the researchers conducted a population-based cohort study using the THIN (The Health Improvement Network) electronic medical record database of patients registered with United Kingdom general practices. They used 21 years of data collected from January 1994 to February 2015.
The researchers matched each patient who had AD with up to five controls based on age, practice, and index date. Because THIN does not capture AD severity, they used treatment exposure assessed by dermatologic referrals and treatments patients received as proxy for severity. The authors used logistic regression to examine the risks for IBD, UC, and CD in children (aged 1-10) with AD, and in adults (aged 30-68) with AD, and they compared their outcomes with the outcomes for controls.
In the pediatric cohort, the team compared 409,431 children who had AD with 1.8 million children without AD. Slightly more than half were boys. In the adult cohort, they compared 625,083 people who had AD with 2.68 million controls, and slightly more than half were women. Data on race or ethnicity were not available, the authors wrote, but the THIN database is considered to be representative of the UK population.