Background/Purpose: Children with JIA are at risk for cardiovascular disease and obesity compounds this risk.  There is limited data on the prevalence of elevated BMI in JIA patients (pts) and its effects on disease activity and physical function.  This study aims to assess the prevalence of obesity and its effects on JIA pts in the Pediatric Rheumatology Care and Outcome Improvement Network (PR-COIN).  We hypothesized that the pts with a high BMI would have worse outcomes.

Methods: We evaluated the de-identified data of JIA pts entered between 6/2010 and 7/2015. Data collected included demographics, height, weight, and pain, CHAQ, Juvenile Arthritis Disease Activity Score (JADAS), and pt and physician global assessment scores (PGA, MDGA). BMI measures body fat based on height and weight (kg/m²).  The average BMI is compared to typical values for other children of the same age and gender. Univariate statistics were used to describe the sample.  To compare outcomes across subgroups and across time, a Wilcoxon Rank sum test and a Wilcoxon Sign Rank test was performed, respectively.

Results: 3317 pts were enrolled in the database across 13 sites in the US and Canada [Tables 1,2].  125 pts were excluded due to missing data for a final sample of 3192 (17,451 visits). Mean age was 7.7 ± 4.9 years, and mean disease duration was 5.4 ± 4.4 years. Table 3 compares the outcome measures of overweight/obese (ov/ob) to normal/underweight JIA pts.    All ov/ob except systemic and undifferentiated pts had higher pain scores (p<0.0001).  Ov/ob oligo-, psoriatic, and ERA pts had higher CHAQ and MDGA scores (p<0.05).  Ov/ob polyarthritis pts had worse disease activity, MDGA, CHAQ scores and more office visits (p<0.0001). Ov/ob systemic pts had the shortest disease duration prior to starting MTX (p=0.001) and more office visits (p<0.0001).  Ov/ob undifferentiated pts had the shortest disease duration prior to the first course of steroids (p<0.04) and a longer disease duration prior to starting MTX (p<0.003) and biologics (p<0.0001) (data not shown).  There was no difference in years to start steroid, MTX or biologic based on overweight status.

Conclusion: Results suggest that ov/ob pts have worse pain, disease, function and more office visits than underweight/normal weight JIA pts.  Goals of treatment should not only include arthritis control, but dietary and exercise treatment and recommendations. 

Table 2. JIA Patients and Health-Related Quality of Life Assessments*

* Presented as median [interquartile range]; MDGA=physician global assessment; CHAQ=Childhood Health Assessment Questionnaire; PGA=Patient GA.  † Duration of Morning Stiffness: 1: No Stiffness; 2: <15 min; 3: 15-30 min; 4: 30 min-1 hr; 5: 1-2 hr; 6:2-4 hr; 7:4- 8hr; 8: >8 hr