ATLANTA — Age at onset of psoriasis determines whether psoriasis or psoriatic arthritis starts first in patients with psoriatic arthritis, according to data from the PsART-international web-based registry presented here.
“We know that usually psoriasis starts first in almost 75% [of cases] — in 15% of cases psoriasis and arthritis start together, and 10% of cases are arthritis first,” Umut Kalyoncu, MD, professor in internal medicine and rheumatology at the Hacettepe University, Faculty of Medicine, Ankara, Turkey, said during a press conference. “There is some clue into the interrelationship between psoriasis and arthritis. In this work, we wanted to explain the reason for this delay in arthritis-first and psoriasis-first cases.”
Kalyoncu and colleagues extracted data on demographics, family history, psoriasis type, site of psoriasis onset and observed components of PsA from the web-based PsART-international registry of patients with PsA receiving care in Turkey, Italy and Canada. They established three groups: arthritis first (n = 71), psoriasis first (n = 1,251) or psoriasis and arthritis occurring at the same time (n = 309), further defined by the onset of skin and joint symptoms within 12 months.
A linear regression model using demographic, skin disease and arthritis characteristics was developed to determine the primary outcome measure: time from skin disease to arthritis, elapsed in months.
Kalyoncu reported that age at psoriasis onset determined whether psoriasis or PsA would appear first. Specifically, age at PsA diagnosis was almost similar in all groups: 41 to 42 years; however, in the PsA first group, psoriasis started at age 48 years and in the psoriasis first group psoriasis started at age 29 years.
Regression analysis revealed a 65-month delay from psoriasis to arthritis onset when other independent variables are set to their baseline levels, also termed the “intercept.” What’s more, pustular psoriasis was associated with arthritis onset 2 years earlier than the intercept, and nail involvement, plaque psoriasis and family history of psoriasis were associated with an increased delay of 2 years for each.
“The results are very important for us because [they show that] if you see the patients and if they have pustular psoriasis, we can say psoriatic arthritis will start earlier, and if you see plaque psoriasis we can say psoriatic arthritis will start later.” – by Stacey L. Adams
Tascilar K, et al. Abstract #2854. Presented at ACR/ARP Annual Meeting, Nov. 8-13, 2019; Atlanta.
Disclosure: Kalyoncu and colleagues report no relevant financial disclosures.