The following article is a part of conference coverage from the 2019 American College of Rheumatology/Association of Rheumatology Professionals (ACR/ARP) Annual Meeting, being held in Atlanta, Georgia. The team at Rheumatology Advisor will be reporting on the latest news and research conducted by leading experts in rheumatology. Check back for more from the 2019 ACR/ARP Annual Meeting.
ATLANTA — Potential pathophysiologic triggers for psoriasis, psoriatic arthritis (PsA), ankylosing spondylitis (AS), and rheumatoid arthritis (RA) are similar and demonstrate some commonalities across all 4 conditions, according to research results presented at the 2019 American College of Rheumatology/Association of Rheumatology Professionals (ACR/ARP) Annual Meeting, held November 8 to 13, 2019, in Atlanta, Georgia.
Researchers performed a series of case-control studies comparing the strength of association of selected potential risk factors for the development of psoriasis, PsA, AS, and RA. Studies were performed in The Health Improvement Network, a general practitioner database in the United Kingdom, and included data from 1994 to 2015. Patients with at least 1 code for any of the 4 conditions were matched with up to 10 healthy controls from the general population based on age, sex, practice, and year of diagnosis.
The cohort included data of 7594 incident PsA cases, 3253 incident AS cases, 111,375 incident psoriasis cases, and 28,341 incident RA cases. These data were matched to 75,930, 32,530, 1,113,345, and 282,226 healthy controls, respectively.
At diagnosis, median ages were 48.3 years (interquartile range [IQR], 38-59 years), 40.7 years (IQR, 31-54 years), 43.1 years (IQR, 31-54 years), and 59.9 years (IQR, 48-71 years) for PsA, AS, psoriasis, and RA, respectively. While sex was balanced in psoriasis, more women had RA and more men had AS (68% and 70%, respectively). Overall, the mean follow-up time ranged from 6.4 to 7.2 years and was slightly longer among healthy controls.
Results of univariate analyses indicated that previously identified PsA risk factors, including obesity, uveitis, and trauma, were replicated. Smoking was identified as a risk factor for RA, consistent with previous research. Some similar risk factors were identified across all 4 diseases, including a positive association between pharyngitis, irritable bowel disease, and uveitis, and a similarly strong protective effect for statins. Skin-based risk factors, including skin infections and trauma, were associated with PsA; joint trauma was also associated with PsA, and diarrheal infections were associated with both PsA and AS.
In the multivariate models, most risk factors maintained statistical significance, although the final models slightly differed by sex.
“This set of parallel case-control studies identifies differences between PsA, psoriasis, AS, and RA that supports the previous theories of pathophysiologic triggers related to these diseases but also demonstrates some commonalities between diseases,” the researchers concluded.
Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
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Ogdie A, Wang X, Love TJ, Thrastardottir T, Dubreuil M, Gelfand J. Shared and differing risk factors for PsA, psoriasis, AS, and RA: a series of case-control studies. Presented at: 2019 ACR/ARP Annual Meeting; November 8-13, 2019; Atlanta, GA. Abstract 2852.