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March 25, 2016
The British Journal of Dermatology
TAKE-HOME MESSAGE
- The association between psoriasis and inflammatory bowel disease (IBD) was studied in this nationwide Danish cohort trial. Investigators found that the risk of IBD increased as psoriasis disease severity increased.
- The adjusted incidence rate ratios (IRRs) of ulcerative colitis were 1.49, 1.56, 1.96, and 2.43 for mild psoriasis, severe psoriasis based on hospitalization, severe psoriasis based on medication prescribed, and psoriatic arthritis, respectively; adjusted IRRs of Crohn’s disease were 1.28, 2.56, 2.85, and 3.42, respectively.
Abstract
BACKGROUND
Psoriasis, Crohn’s disease (CD), and ulcerative colitis (UC) are chronic inflammatory disorders with overlapping genetic architecture. However, data on frequency and risk of CD and UC in psoriasis are scarce and poorly understood.
OBJECTIVES
To investigate the association between CD and UC in patients with psoriasis.
METHODS
All Danish individuals aged ≥18 years between 1 January 1997 and 31 December 2012 were linked in nationwide registers. Psoriasis severity was defined in two models; hospital visits or medication. Incidence rates (IRs) per 10,000 person-years were calculated, and incidence rate ratios (IRRs) were estimated by Poisson regression.
RESULTS
In the total cohort (n=5,554,100) there were 75,209 incident cases of psoriasis, 11,309 incident cases of CD, and 30,310 incident cases of UC, respectively, during follow-up. Adjusted IRRs (95% confidence intervals) of CD were 1.28 (1.03-1.59), 2.56 (1.87-3.50), 2.85 (1.72-4.73), and 3.42 (2.36-4.95) in patients with mild psoriasis, severe psoriasis (hospital), severe psoriasis (medication), and psoriatic arthritis, respectively. Similarly, adjusted IRRs of UC were 1.49 (1.32-1.68), 1.56 (1.22-2.00), 1.96 (1.36-2.83), and 2.43 (1.86-3.17), respectively. The 10-year incidence of CD was 2-5 per 1,000 patients and of UC 7-11 per 1,000 patients dependent on psoriasis severity and presence of psoriatic arthritis. Additionally, an increased risk of incident psoriasis was found following CD or UC.
CONCLUSIONS
We observed a psoriasis-associated increased risk of CD and UC, which was higher in severe psoriasis, and an increased risk of psoriasis in patients with IBD. Increased focus on gastrointestinal symptoms in patients with psoriasis may be warranted.