Changes in body mass index in children with juvenile idiopathic arthritis treated with tumor necrosis factor inhibitors

Objective. To evaluate changes in body mass index (BMI) among cohorts of children with juvenile idiopathic arthritis (JIA) with and without tumor necrosis factor (TNF) inhibitor therapy. Methods. We performed a retrospective chart review of children with JIA who newly initiated TNF inhibitor therapy and had at least 1 year of subsequent followup (TNF cohort). We also included children with JIA and at least 1 year of followup without any TNF inhibitor therapy (comparator cohort). Children with systemic arthritis were excluded. Age and sex specific BMI z-scores and their corresponding categories (normal, overweight, obese) were determined. We compared changes from a baseline visit to the last followup visit using t-test for BMI z-scores and chi square and Kruskal-Wallis tests for BMI categories. Results. The TNF cohort had 167 patients; the comparator cohort had 37. The median study followup was 2.8 and 2.2 years, respectively. The cohorts had similar age, sex, race, weight, and height distributions. The TNF cohort had a statistically significant increase in BMI z-score from baseline (+0.15; p = 0.02) that was not significantly different from the increase (+0.09) observed in the comparator cohort (p = 0.5). There was no significant change in the proportions of overweight and obese children in the TNF cohort compared to baseline (p = 0.6) or compared to the change in the comparator cohort (p = 0.2). Conclusion. Over more than 2 years of followup, we did not observe a significant increase in BMI among children with JIA receiving TNF inhibitor compared to those not receiving it. The Journal of Rheumatology