Background/Purpose:

MRI studies on RA revealed that subclinical synovitis is common in patients in clinical remission and it is responsible for structural damage progression. MRI-detected synovitis in JIA patients with clinically inactive disease was also reported. Due to the lack of longitudinal studies in JIA, it is unclear whether this phenomenon entails an higher risk of joint damage progression and should affect treatment decisions.

Objectives: to assess the prevalence of MRI-detected synovitis in a cohort of JIA patients in clinical remission and to evaluate its association with disease flare and damage progression.

Methods:

all JIA patients who met the Wallace criteria for clinical remission and underwent contrast-enhanced MRI at the Study Unit between 2007 and 2015 were included. MRIs were scored by two independent readers according to the Outcome Measure in Arthritis Clinical Trials (OMERACT) Rheumatoid Arthritis Scoring System (RAMRIS). Joint damage progression was assessed by conventional radiography (CR) according to the adapted versions of the Sharp/van der Heijde score and to the Childhood Arthritis Radiographic Score of the Hip. The concordance between the readers was assessed using kappa statistics. Categorical data were analyzed using chi-squared test and Fisher’s exact test. Comparison of quantitative variables was performed by the non-parametric Mann–Whitney U-test. A logistic regression model was applied to perform multivariate analysis of the radiographic damage risk factors.

Results: a total of 90 patients (75 F; mean age 13.8 years; mean disease duration 8.5 years; mean follow-up duration 2.9 years) were included. Fourteen out of 90 patients (15.6%) were in remission off medication, while 76/90 patients (84.4%) were in remission on medication. Forty-five patients were assessed by MRI in the wrist, 30 in the hips, 13 in the ankle and 2 in the knee. Fifty-seven patients (63.3%) had evidence of synovitis on MRI. The inter-observer agreement for presence/absence of synovitis was good (k=0.74; 95% CI: 0.5-0.9). Forty-three out of 57 patients (75,4%) with synovitis experienced a disease flare versus 11 out of 33 patients (33.3%) who hadn’t any synovial inflammation (P<0.0001). Radiographic progression was assessed in 54/90 patients for whom follow-up CRs were available and was detected in 19/54 patients (35.2%). A significant association between systemic JIA subtype and deterioration of joint damage was found (P=0.027). MRI-detected bone marrow oedema (BMO) and the baseline radiographic damage scores were also related to structural progression (P=0.002). The multivariable logistic regression analysis showed that only BMO score ≥3 independently contributed to explain radiographic damage progression (OR 4.82; 95% CI: 1.0-23.2; P=0.035).

Conclusion:

A sizeable proportion of patients in clinical remission has MRI evidence of persistent joint inflammation. Subclinical synovitis was significantly associated with disease flare, while BMO showed remarkable promise in predicting joint destruction. These findings support the utility of MRI for the assessment of JIA patients in clinical remission and may have important clinical implications for their management.

« Back to 2017 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/predictive-value-of-magnetic-resonance-imaging-in-patients-with-juvenile-idiopathic-arthritis-in-clinical-remission/