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

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.

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.

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.

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.