Psoriasis Shows Bidirectional Association With IBD

By Will Boggs MD

October 01, 2019

NEW YORK (Reuters Health) - People with psoriasis have an increased risk of inflammatory bowel disease (IBD), and people with IBD have an increased risk of psoriasis, according to a systematic review and meta-analysis.

"The high prevalence of psoriasis in IBD, and in particular the paradoxical psoriasis following treatment with biologics, may necessitate a closer collaboration between gastroenterologists and dermatologists," said Dr. Alexander Egeberg from Herlev and Gentofte Hospital, University of Copenhagen, in Denmark.

"When psoriasis patients present symptoms of IBD, or vice versa, a cross-specialty collaboration may help optimize the treatment strategy in order to manage both disease in the best possible way," he told Reuters Health by email.

Psoriasis and IBD appear to have overlapping pathogenetic mechanisms and a number of shared genetic susceptibility loci, and several epidemiological studies have reported an increased risk of IBD in psoriasis and vice versa.

Dr. Egeberg's team sought to quantify the prevalence and association between psoriasis and IBD in their systematic review and meta-analysis of 93 studies.

Overall, the prevalence of psoriasis in patients with IBD was 4.2% (3.8% in adults and 8.4% in children and adolescents). The prevalence was about twice as high in IBD patients treated with TNF inhibitors (6.7%) than in those not receiving biologics (3.1%), the researchers report in the Journal of Crohn's and Colitis, online August 30.

Based on data from 32 studies that examined subtypes of IBD, the prevalence of psoriasis was 3.6% in patients with Crohn's disease (3.2% in adults and 7.3% in children and adolescents) and was 2.8% in patients with ulcerative colitis (2.7% in adults and 8.9% in children and adolescents).

"To me, a very interesting finding was the strikingly high prevalence of psoriasis among children with IBD, where more than 8% of patients also had psoriasis," Dr. Egeberg said. "Although speculative, this could suggest that those with early onset may have a distinct risk profile with a higher risk than those with late-onset of their disease."

Conversely, the prevalence of IBD in patients with psoriasis was 1.2% (1.3% in adults and 0.6% in children and adolescents) and was similar in patients treated with TNF inhibitors (0.8%) and in those not treated with TNF inhibitors (1.2%).

Among patients with psoriasis, the prevalence of Crohn's disease was 0.7% (0.7% in adults and 0.4% in children and adolescents), and the prevalence of ulcerative colitis was 0.5% (0.6% in adults and 0.2% in children and adolescents).

Based on data from eight studies, the presence of IBD was associated with 80% greater odds of having psoriasis (2.0-fold increased odds with Crohn's disease and 50% increased odds with ulcerative colitis), and the presence of psoriasis was associated with 2.0-fold increased odds of IBD (2.2-fold increased odds of Crohn's disease and 60% higher odds of ulcerative colitis).

The researchers note that the included studies had a high level of heterogeneity and a significant risk of publication bias.

According to the U.S. Centers for Disease Control and Prevention (CDC), the prevalence of IBD in the general population is around 1.3%, and the prevalence of psoriasis is around 3.1%.

"From the dermatologists' point of view, these findings are reassuring," Dr. Egeberg said. "In recent years, a number of new therapies have been developed for psoriasis. Some of these have been shown to exacerbate IBD, so the extremely low prevalence (less than 1 percent) of Crohn's disease or ulcerative colitis in psoriasis suggests that the presence of IBD should not be a major concern when prescribing such therapies for psoriasis."


J Crohns Colitis 2019.