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

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.