Analysis of disease activity, functional disability and articular damage in patients with juvenile idiopathic arthritis: a prospective outcome study.

OBJECTIVES

We longitudinally studied outcomes of patients with juvenile idiopathic arthritis (JIA) using the Childhood Health Assessment Questionnaire (CHAQ) for physical disability and the Juvenile Arthritis Damage Index for articular (JADI-A) and extra-articular damage (JADI-E), and we correlated them with various disease activity variables.

METHODS

Eighty-seven patients with JIA were included in the prospective follow-up study with median age 14 years (4.6-18.0), disease duration 5.2 years (2.0-18.9) and follow-up of 4.0 years (2.0-5.2). Besides JADI-A and JADI-E, and the assessment of active joints count, joints with limited mobility, ESR, CHAQ and radiographic damage of joints was also done. A correlation analysis of CHAQ and JADI with various disease activity variables was performed.

RESULTS

The patient's distribution of JIA subtypes were polyarticular (32), systemic onset (13), oligoarticular (31), and enthesitis related arthritis (11). After a follow-up period, 46% patients had active disease compared to 83% patients at baseline (p<0.01). The CHAQ disability index improved over baseline, while radiological damage (p<0.001) and JADI-A and JADI-E scores worsened (p<0.001). CHAQ and JADI significantly correlated with the majority of disease activity variables. CHAQ DI was significantly higher in the patients with coxitis (p<0.01) and wrist arthritis (p<0.001). The most pronounced deterioration in articular damage (JADI-A) was observed in patients with sJIA (3.69 at baseline vs. 5.69 at study endpoint).

CONCLUSIONS

The improvement of functional disability (CHAQ DI) was observed over the course of the disease, whereas radiological joint damage, JADI-A and JADI-E scores worsened. Children with systemic JIA, wrist arthritis, coxitis and prolonged active disease are at higher risk of progression of severe disability.