The age of psoriasis onset determines whether arthritis or psoriasis starts first in patients with psoriatic arthritis (PsA).
PsA is a chronic arthritis that typically occurs in patients with skin psoriasis, but it can occur in the absence of skin psoriasis, particularly in those with a family history. The interrelationships between characteristics of skin psoriasis, arthritis, and the timing of arthritis are not well studied, the investigators said.
Researchers used PsART-International, which is a web-based registry of PsA patients under routine care in Turkey, Italy, and Canada. PsART-International includes detailed disease history about the type and onset of skin and joint disease.
The study included 1631 patients; 71 had arthritis first, 309 had synchronous onset, and 1251 had psoriasis first. Data pulled from the registry included demographic characteristics, family history of psoriatic disease (regardless of skin or arthritis), types of skin psoriasis, site of skin psoriasis onset, and components of psoriatic arthritis observed.
The primary outcome was the absolute time elapsed in months after skin disease to arthritis (negative values indicating arthritis onset before psoriasis), and the investigators used a linear regression model. Analysis showed a 65-month delay of arthritis onset after psoriasis when other independent variables are set to their baseline values.
Results of the regression analysis showed that the model intercept, or delay of arthritis after psoriasis when other independent variables are set to their baseline values, is 65 months. Pustular psoriasis is associated with onset of arthritis about 2 years earlier than the intercept interval.
Additionally, there is an increased delay for nail involvement, plaque psoriasis or family history of psoriasis from psoriasis to arthritis by approximately 2 years for each characteristic.
“The PsART-International cohort focuses on PsA patients in whom musculoskeletal symptoms start before skin lesions, which is approximately [5 to 10%] of all PsA patients. We need more patients to determine related factors,” Umut Kalyoncu, MD, professor, internal medicine and rheumatology, at Hacettepe University in Turkey, and the study’s lead author, said in a statement. “PsA is a heterogeneous disease for clinical presentation and treatment response. If patients with arthritis first are really a different subgroup, it means that treatment response and prognosis could be different from others. Indeed, in our cohort, achieving minimal disease activity is statistically less frequent in patients with arthritis first.”
Tascilar K, Zehra Aydin S, Akar S, et al. Delay between the onset of psoriasis and arthritis in PSA patients from the PsART International Cohort. Presented at: The American College of Rheumatology Annual Meeting, November 8-13, 2019; Atlanta, Georgia. Abstract #2854.