Individuals with psoriasis are at a 5 fold higher risk for other immune-mediated inflammatory diseases (IMIDs) compared with the general population, according to study results published in the Journal of the American Academy of Dermatology.

Researchers aimed to investigate the chronology of IMIDs relative to psoriasis because of the lack of previous chronological assessment. They used routinely collected data from the Danish nationwide administrative registries to examine the occurrence of IMIDs in individuals with psoriasis (n = 10,923) and general population control participants (n = 109,230), between January 1, 2007 and December 31, 2016. To qualify, individuals must have received ≥1 diagnostic code for psoriasis. Individuals with the diagnosis of psoriasis before January 1, 2007 were excluded. The IMIDs selected were multiple sclerosis, psoriatic arthritis (PsA), pyoderma gangrenosum, rheumatoid arthritis, ankylosing spondylitis, systemic lupus erythematosus, celiac disease, primary sclerosing cholangitis, primary biliary cholangitis, type 1 diabetes, asthma, sarcoidosis, Graves’ disease, iridocyclitis, ulcerative colitis, and Crohn disease.

The mean age of individuals with the first-ever diagnosis of psoriasis and control participants, 52.9% of whom were women, was 52.1±15.5 years. One-fifth (n = 2181) of individuals with psoriasis developed ≥1 IMID, with a 5-fold increased risk compared with the general population. Most IMIDs occurred before the diagnosis of psoriasis, except for PsA. Psoriasis was significantly associated with having multiple IMIDs (odds ratio [OR] 15.2; 95% CI, 11.6-20). The highest number of coexisting IMIDs in one individual before psoriasis diagnosis was 5. After the diagnosis of psoriasis, 14.7% of individuals with psoriasis developed ≥1 IMID. The most commonly occurring IMIDs before a diagnosis of psoriasis were PsA (7.2%), asthma (3.7%), rheumatoid arthritis (3.4%), and type 1 diabetes (2.5%). After the onset of psoriasis, the dominating comorbidity was PsA (10.5%). Human leukocyte antigen B27 was significantly more frequent among individuals with psoriasis.

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The limitations of this study included the lack of clinical measurement; this was an observational study that collected administrative data, and objective measurement of psoriasis severity was missing. Also, the date of psoriasis diagnosis did not necessarily represent the exact time of the onset of skin manifestations. This uncertainty represented a limitation because many rheumatologists depend on a psoriasis diagnosis before giving the diagnosis of PsA.

The researchers concluded that their findings have the potential to provide new insights in understanding the pathophysiological mechanism of concurrent IMIDs in individuals with psoriasis. Moreover, because PsA among patients with psoriasis was associated with additional IMIDs, this group might require increased diagnostic awareness among clinicians.

Multiple authors declared associations with the pharmaceutical industry. Please see original reference for a full list of authors’ disclosures.

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Reference

Andersen YMF, Wu J, Thyssen JP, Egeberg A. Chronological order of appearance of immune mediated inflammatory diseases relative to diagnosis of psoriasis [published online April 19, 2019]. J Am Acad Dermatol. doi:10.1016/j.jaad.2019.04.033