Background/Purpose:

Radiographic damage was recently considered to be a feature of poor prognosis in cases of polyarticular juvenile idiopathic arthritis (pJIA). However, most radiographic studies did not differentiate pJIA from other subtypes of JIA and did not include a control group. Furthermore little is known about radiographic damages in pJIA persisting into adulthood. The objective of our study was to describe structural peripheral involvement in pJIA persisting into adulthood and compare observed lesions to those seen in rheumatoid arthritis (RA) using a cross-sectional observational study.

Methods:

All consecutive pJIA followed in a transition program were included. Age, sex, disease duration, medical or surgical treatments were collected. Laboratory tests (ESR, CRP, Rheumatoid Factor (RF) and anti-CCP) and standard radiographies of the hands and wrists, feet and hip were performed. A RA control group (<55years), matched for sex and disease duration, was recruited. Radiographs were analyzed by two independent radiologists blinded to the diagnosis. Structural lesions on the hands and feet were assessed by the modified version of Larsen's scoring method. The hands and feet scores range from 0 to 110 and from 0 to 50, respectively. Hips were assessed for presence of coxitis. Student and Fischer exact test were used.

Results:

58 pJIA (48 females/10 males) and 59 RA (52/7) were included. Respectively, mean age was 23.5±10.0 years and 43.2±9.6 years and mean disease duration 13.1±11.1 and 12.2±7.1 years. 60% and 80% were RF positive and 57% and 78% were anti-CCP positive (p=0.02). The inter-observer concordance coefficient kappa was 0.614 between the two investigators. Radiographs showed hand lesions in 45/58 (78%) pJIA and 50/58 (86%) RA-patients, feet lesions in 39/58 (67%) pJIA and 47/59 (80%) RA-patients and coxitis in 16/54 (30%) pJIA and 8/47 (17%) RA-patients (p=NS for all comparisons). Mean hands and feet scores were 17.9±21.8 and 7.7±10.8 in pJIA and 18.5±17.6 and 9.9±11.3 in RA, respectively (p=NS). Specificities to juvenile forms were a lower frequency of proximal interphalangeal joints involvement and a higher risk of bilateral coxitis (81% vs. 25% (p=0.007, OR=13 [1.701-99.375]) than adult RA.  RF-positive patients differed from RF-negative patients only by a shorter disease duration (10.4±9.3 vs. 17.3±12.6, p=0.02). Comparison between RF positive and negative pJIA showed a trend for more frequent hand and feet lesions with a higher carpal score in RF-positive patients. There were less coxitis (5/31 vs. 11/23) in RF-positive subgroup (p= 0.01). In pJIA, presence of radiographic damage correlated with a more severe disease phenotype.

Conclusion:

Structural peripheral damages are frequent in young adults with pJIA and correlated with a more severe disease. A specific feature to pJIA seems to be a high risk of bilateral coxitis. This requires a particular following and monitoring of pJIA patients with unilateral hip involvement to prevent bilateralization.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/radiological-peripheral-involvement-at-hands-feet-and-hips-in-young-adults-with-polyarticular-idiopathic-juvenile-arthritis/