Prognostic factors for radiographic progression, radiographic damage, and disability in juvenile idiopathic arthritis

Abstract

Objective To investigate the rate of radiographic progression and identify prognostic factors of radiographic progression, radiographic damage, and physical disability in juvenile idiopathic arthritis (JIA). Methods Ninety‐four JIA patients with a median disease duration of 1.1 years were followed up prospectively for a median of 4.5 years. Bilateral wrist radiographs were obtained at baseline, at 1 year, and at the last followup visit. Radiographic damage was assessed by the carpal length (Poznanski score), and physical disability by the Childhood Health Assessment Questionnaire (C‐HAQ). Yearly radiographic progression, the Poznanski score at the final visit, and the C‐HAQ score at the final visit were used as outcome measures. Baseline parameters included demographic, clinical, laboratory, and radiographic data. Results The mean ± SD Poznanski score was −1.2 ± 1.3 at baseline, −1.7 ± 1.8 at the 1‐year visit, and −1.9 ± 2.2 at the final visit (P < 0.0001). Radiographic progression was greater during the first year (mean ± SD −0.5 ± 1.1) than between the 1‐year visit and the final visit (−0.2 ± 1.3). The mean yearly radiographic progression during the entire study period was −0.1 ± 0.4. Logistic regression analysis revealed that radiographic progression during the first year was the only baseline parameter that was predictive of all 3 study outcomes. The final Poznanski score was also predicted by the baseline Poznanski score, whereas female sex was protective against radiographic progression. Conclusion We identified the prognostic factors for poorer outcome in polyarticular‐course JIA. The changes in the early Poznanski score can be used to predict long‐term joint damage and physical disability.