Background/Purpose

National registry cross-sectional data show significant differences in patient-reported outcomes (PROs) across juvenile idiopathic arthritis (JIA) subtypes. This study aimed to assess predictors of PROs in JIA in a tertiary care clinic setting.

Methods

This is a retrospective study of children meeting ILAR JIA criteria evaluated in a tertiary pediatric rheumatology clinic between 2010-2012. Pain over the past week was assessed with a visual analogue scale (VAS; 0,10). Function was estimated with the childhood health assessment questionnaire (CHAQ; 0, 3). Physician global disease activity was measured using a VAS (0,10). We tested the association of clinical characteristics with pain and function using multivariable linear and ordinal logistic regression, accounting for clustering by subject. Pair-wise correlation was used to compare the association of physician disease assessment and each PRO.

Results

During the study period there were 542 subjects evaluated at 2,689 visits. The distribution of JIA categories was oligoarticular (37%), polyarticular RF+ (3%), polyarticular RF- (19%), systemic (8%), psoriatic (9%), enthesitis-related arthritis (ERA) (18%), undifferentiated (6%). Patients with ERA and undifferentiated reported higher pain intensity (p<0.01), higher pain prevalence (p<0.01), and poorer function (p<0.01) than other JIA categories. In multivariable analyses, older age, female sex, higher active joint count, NSAID use, DMARD use, and the ERA and undifferentiated categories were associated with higher pain scores (Table). Higher active joint count, NSAID use, glucocorticoid use, and ERA were associated with worse function. In patients with ERA, higher tender enthesitis count and female sex were significantly associated with higher pain intensity and poorer function. In patients with undifferentiated arthritis, higher active joint count and glucocorticoid use were associated with worse function.  Correlation between the physician assessment of disease activity and patient-reported pain intensity and function were low (r=0.5, 0.4, respectively).

Conclusion

At our tertiary care center children with ERA and undifferentiated JIA had higher pain intensity and more frequent pain than other JIA categories. These results suggest that current treatment regimens may not be equally effective across JIA categories or as efficacious for particular disease attributes that are more common in the ERA and undifferentiated categories.