The likelihood of joint inflammation recurrence in previously affected joints during psoriatic arthritis disease course.

Abstract

Objectives: To evaluate the likelihood of joint inflammation recurrence in previously affected joints during the disease course of psoriatic arthritis, and to identify joint-specific predictors associated with recurrence risk using real-world data.

Methods: Patients with PsA followed at the Tel Aviv Medical Center Rheumatology Institute were included. At each visit, the 68-swollen joint count (SJC68) was assessed. The association between baseline joint swelling and recurrence was analysed using mixed-effects logistic regression, adjusting for joint location and for follow-up visit. An interaction analysis was conducted to determine the association of each joint location.

Results: A total of 492 patients were included, with a median of 6 (IQR 4-9) follow-up visits. Of these, 44% were male, with a mean age at baseline of 48 y/o (SD 15), and a mean disease duration of 1 year (1.9). At baseline, 420 (85%) patients had at least 1 swollen joint, with a median SJC68 of 2 (1-5). Among the 33,456 joints assessed, 1402 were swollen at baseline (4.2%), and 514 (36.7%) of them recurred during follow-up. Mixed-effect logistic regression showed that baseline swelling predicted future swelling (odds ratio 2.88, 95% CI 2.61-3.18) with variation by joint location. This association was not modified by sex, age, or disease duration.

Conclusions: This study identified a strong association between baseline joint swelling and subsequent swelling episodes in patients with PsA. This association varied by joint and remained significant when limited to the most frequently swollen joints.