Risk for developing PsA remains ‘linear’ among psoriasis patients
SAN DIEGO — Contrary to previous findings, the risk for psoriatic arthritis was persistent among patients with psoriasis and did not wane over time, according to a presentation at the 2019 Congress of Clinical Rheumatology West.
“I used to teach people that if a patient with psoriasis does not develop psoriatic arthritis within 10 years, they were not likely to get it — that is wrong!” Dafna D. Gladman, MD, director of the psoriatic arthritis program at Toronto Western Hospital and a member of the National Psoriasis Foundation Medical Board, told attendees. “They can get it, even up to 30 years.”
Gladman noted that “the incidence and prevalence of psoriatic arthritis has evolved over the years” — approximately 20% of patients with psoriasis worldwide also have psoriatic arthritis, according to a recent meta-analysis by Alinaghi and colleagues.
“We have conducted the only prospective study of psoriasis patients to determine the incidence and prevalence of psoriatic arthritis,” Gladman said, citing the 2016 study by Eder and colleagues, which assessed patients with psoriasis (n = 464) who did not have a diagnosis of arthritis at the time of enrollment. Patients were diagnosed by a dermatologist and reviewed by a rheumatologist prior to inclusion in the study, in which they were followed for 8 years.
Examining lifestyle habits, comorbidities, psoriasis activity and medication, Eder and colleagues used Cox proportional hazards models, involving fixed and time-dependent explanatory variables to obtain estimates of the relative risk of the onset of PsA, while using an event-per-years analysis to establish annual incidence of PsA.
According to the researchers, 51 patients were confirmed for PsA, having been assessed by a rheumatologist, and nine patients were suspected to have psoriatic arthritis because they scored high on the screening questionnaire.
“What we found was that the annual incidence of psoriatic arthritis among these patients was 2.7% if you looked at confirmed cases of PsA, and 3.2% if you included the suspected cases,” Gladman said, “However, the important thing to appreciate though is that the risk of developing PsA was linear. It behooves us to teach our rheumatology and family medicine colleagues that when a patient comes in with psoriasis, they should ask about joint pain, and if they report joint pain, they need to be referred to a rheumatologist.”—Robert Stott
- Gladman DD. 2019 Update in Psoriatic Arthritis. Presented at: Congress of Clinical Rheumatology West; September 26-29, 2019; San Diego.
- Alinaghi F, et al. J Am Acad Dermatol. 2018;doi:10.1016/j.jaad.2018.06.027.
- Eder L, et al. Arthritis Rheumatol. 2016;doi:10.1002/art.39494.
Disclosure: Gladman reports consulting fees, speaking fees, and/or honoraria from AbbVie, Amgen, Bristol-Myers Squibb, Celgene, Eli Lilly, Galapagos, Gilead, Janssen, Novartis, Pfizer and UCB — all in amounts of less than $10,000 each.