Clinical and laboratory features of juvenile idiopathic arthritis with wrist involvement: Results of a retrospective cohort study.

Background: Previous studies in the pre-biological era showed an association of wrist inflammation in juvenile idiopathic arthritis (JIA) with progressive disease course, polyarticular involvement and failure of methotrexate treatment.

Aim: To describe features of JIA, associated with wrist arthritis.

Methods: Data from about 753 JIA patients were included in this retrospective cohort study. The clinical and laboratory features of patients with and without wrist involvement were analyzed.

Results: Wrist involvement was found in oligoarthritis (5.8%), RF(-)/RF(+) polyarthritis (44.9%/15.0%), enthesitis-related arthritis (17.7%), and systemic (58.6%) JIA categories. Unilateral wrist involvement was typical for oligoarthritis patients, bilateral involvement was either equal to that of unilateral involvement or was more frequent in other categories. Wrist arthritis was found to be associated with female sex, a low incidence of uveitis, and more indications of systemic inflammation, including elevated levels of C-reactive protein, erythrocyte sedimentation rate, and platelets, as well as involvement of the cervical spine, temporomandibular, shoulder, elbow, metacarpophalangeal, proximal interphalangeal, distal interphalangeal, hip, ankle, and tarsus arthritis. The number of patients with hip osteoarthritis and hip replacement was also higher. Wrist arthritis was associated with a lower probability of achieving remission [hazard ratio (HR) = 1.3 (95%CI: 1.0-1.7), P = 0.055], and a higher probability of being treated with biologics [HR = 1.7 (95%CI: 1.3-2.10, P = 0.00009)].

Conclusion: Wrist arthritis in JIA patients is a marker of a severe disease course, characterized by more intensive inflammation, unfavorable outcomes, and. requiring more intensive treatment with early administration of biologics. Close monitoring of wrist inflammation with ultrasound and MR assessment with early biological treatment might improve the outcomes.