Background: Growth hormone (GH) treatment stimulates growth in short children with juvenile idiopathic arthritis (JIA). The extent to which this therapy increases final height is not known.

Methods: 31 growth retarded children with systemic and polyarticular idiopathic arthritis were enrolled in this controlled study. After a mean observational time of 8.4 years final height was reached in 13 patients (7f, 6m) treated with GH for a mean of 6.7 years in a dose of 0.33 mg/kg bodyweight per week. 18 patients (12f, 6m) served as an untreated control group.

Results: Mean increment in height in the treatment group was 1.6 ± 0.8 SD whereas the patients of the control group lost 0.7 ± 1.8 SD. Overall, mean final height in the treatment group was -1.6 SD and in the control group -3.4 SD. More GH treated patients reached a final height within target height than untreated patients (11/13 vs. 4/18). Disease activity markers had a significant influence on height outcome. After adjustment for baseline and average disease activity the difference between treatment and control group was still significant (mean 1.5 SD). Patients with a moderate overall disease activity profited most from GH treatment. No adverse events were noted throughout the study.

Conclusion: Our data suggest that long-term growth hormone therapy has a beneficial effect on growth and final height in the majority of growth retarded children with severe forms of JIA.