Adapted versions of the Sharp/van der Heijde score are reliable and valid for assessment of radiographic progression in juvenile idiopathic arthritis

Abstract

Objective: To develop adapted versions of the Sharp/van der Heijde radiographic scoring system for use in juvenile idiopathic arthritis (JIA), and to investigate their validity in JIA patients with polyarticular disease.

Methods: The study group comprised 177 patients with polyarticular JIA. Radiographs of the wrist/hand of each patient were obtained at baseline (first observation) and then at 1, 3, 5, 7/8, and 10 years and were assessed independently by 2 pediatric rheumatologists according to different adaptations of the Sharp/van der Heijde method. To facilitate score assignment, the radiograph for each patient was compared with a bone age-related standard. Validation procedures included analysis of reliability, construct validity, and score progression over time.

Results: Interobserver and intraobserver agreement on longitudinal score values and score changes was good for all of the adapted scoring versions (intraclass correlation coefficient >0.85). Score changes over time were moderately to strongly correlated with the clinical indicators of long-term joint damage and with the amount of long-term radiographic damage as measured with the carpo:metacarpal ratio, thereby demonstrating good construct validity. A steady increase in scores over time was observed, with joint space narrowing being the most common form of damage throughout the disease course. The inclusion of 5 new areas appeared to increase the overall construct validity of erosion scores.

Conclusion: Our results show that the adapted versions of the Sharp/van der Heijde score are reliable and valid for the assessment of radiographic progression in patients with JIA.