Etanercept use associated with significant increases in height, weight, BMI in children with arthritis

January 1, 2011

Researchers from the Cincinnati Children's Hospital Medical Center have demonstrated that the tumor necrosis factor-alpha inhibitor etanercept is associated with significant increases in height, weight, and body mass index in children with juvenile idiopathic arthritis, according to a study recently published in Arthritis & Rheumatism.

Key Points

Researchers from the Cincinnati Children's Hospital Medical Center have demonstrated that the tumor necrosis factor (TNF)-alpha inhibitor etanercept is associated with significant increases in height, weight, and body mass index (BMI) in children with juvenile idiopathic arthritis (JIA), according to a study recently published in Arthritis & Rheumatism. Further, these benefits were apparent regardless of whether methotrexate was used concomitantly.

JIA has been linked to growth retardation in children as a result of the chronic inflammation underlying the disease. Edward Giannini, MD, lead author on this new study stressed, "A realistic treatment goal for JIA patients should include therapy aimed at reducing inflammation in an effort to minimize disease-related disability and growth impairment."

In their paper, researchers reported the results of a 3-year, non-randomized evaluation of anthropometric end points of 594 children with systemic or polyarticular (~90%) JIA treated with etanercept (n=103), methotrexate (n=197), or the combination of both drugs (n=294). Patients receiving the biologic agent etanercept in this registry did so as a twice-weekly dose of 0.4 mg/kg or a once-weekly dose of 0.8 mg/kg. Changes from baseline in anthropometric measurements (mean height, weight, and BMI) were reported using percentiles derived from the Centers for Disease Control and Prevention's standardized growth charts. Their analysis showed that patients receiving etanercept or the combination of etanercept and methotrexate experienced statistically significant increases in height (4.8 and 5.6 percentile points), weight (13.0 and 8.4 percentile points), and BMI (ranges: 9.6–13.8 and 2.1–5.2 percentile points, respectively) from baseline. These improvements in anthropometric end points were seen as early as year 1 of treatment. No effect on these parameters was observed in patients receiving methotrexate alone.

SOURCES

Giannini EH, Ilowite NT, Lovell DJ, et al. Effects of long-term etanercept treatment on growth in children with selected categories of juvenile idiopathic arthritis. Arthritis & Rheumatism. 2010;62(11):3259–3264.

Sacks JJ, Helmick CG, Luo YH, Ilowite NT, Bowyer S. Prevalence of and annual ambulatory health care visits for pediatric arthritis and other rheumatologic conditions in the United States in 2001-2004. Arthritis & Rheumatism. 2007;57(8):1439–1445.