Etanercept Improves Height Z-Score Over First 2 Years in Children with JIA

SAN DIEGO, CA—Etanercept is associated with a higher rate of improvement in height z-score over the first 2 years of therapy in patients with juvenile idiopathic arthritis (JIA), according to study results presented at the 2013 ACR/ARHP Annual Meeting.

Approximately 1—17% of children with JIA are reported to have short stature caused by chronic inflammation with or without corticosteroid use. Etanercept, currently licensed in Europe for use in this population, is routinely prescribed after failure of other disease-modifying antirheumatic drugs.

Liannne Kearsley-Fleet, BSc, MSc, and colleagues, at the British Society for Paediatric and Adolescent Rheumatology (BSPAR) created a national etanercept database in 2004 to study vertical growth in patients with severe JIA over the first 2 years of treatment. In addition, study researchers aimed to explore factors associated with improved growth over this same period.

Analysis was limited to 191 children who were treated with etanercept and had complete height data at baseline, 1 year, and 2 years. Median baseline age was 11 years (range 7.3-12.9) and median disease duration at the start of treatment was 3.5 years (1.7-7.1). At baseline, the mean height z-score was 0.74 (1.4) standard deviations below the reference mean.

Patient height at each follow-up was age and sex matched with The WHO Child Growth Standards to calculate a z-score. Any changes in mean height z-score from baseline to 2 years were then recorded and multivariate linear regression helped to identify factors associated with a change in height z-score.

After 2 years of treatment with etanercept, the mean height z-score increased by 0.29 (0.5) to a mean of -0.45 (1.4) standard deviations below the reference mean (P<0.001). A trend was identified towards better improvement in growth over 2 years in children who achieved minimal disease activity at 6 months (47%), but statistical significance was not reached (P=0.249).

Factors associated with an improved height were lower baseline z-score (-0.110 per unit z-score [95% CI -0.162, -0.059] P<0.001) and no steroid use at baseline (-0.190 [95% CI -0.342, -0.037]).

Treatment with etanercept has a higher rate of improvement in height z-score over the first 2 years of treatment, the researchers concluded. In addition, children who did not receive concurrent steroids had a greater improvement, which may indicate that these patients had less severe disease.
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