[Growth hormone therapy in children with growth hormone deficiency: study of dose-response relationship].

BACKGROUND

Despite different age, stature, severity of hormone deficiency and target height children with growth hormone deficiency are usually given a uniform therapeutic dose of the preparation. Knowledge of the basic variables which influence individual therapeutic effects of growth hormone would make it possible to elaborate for individual patients a specific therapeutic strategy with the aim to cath up with the deficiency in height at an appropriate calendar age.

METHODS AND RESULTS

The authors treated for a period of one year, using three different dosages of growth hormone, 25 prepubertal children with growth hormone deficiency (post-stimulation level < 8 mIU/l). Group A (9 children aged 11.2 +/- 2.0 years) were treated with 0.42 IU/kg/week, group B (7 children, aged 11.4 +/- 4.6 years) 0.7 IU/kg/week and group C (9 children, aged 10.2 +/- 2.4 years) 1.0 IU/kg/week. The preparation was administered daily before bedtime by the s.c. route. The growth rate during treatment increased from (mean +/- SD) 2.6 +/- 0.9 to 9.3 +/- 1.5 cm/year (group A), from 2.3 +/- 1.0 to 10.4 +/- 2.5 cm/year (group B) and from 3.1 +/- 0.7 to 12.6 +/- 1.9 cm/year (group C, p < 0.05 as compared with group A). The height age increased per year of treatment significantly more in children of group C (by 2.1 +/- 0.3 year) than in group A (by 1.6 +/- 0.3 year) or in group B (by 1.7 +/- 0.3 year). No difference was found between the groups in the ratio of changes in height and bone age. From 10 analyzed variables the growth rate during treatment is predicted above all by the therapeutic dose (r = 0.60), and to a lesser extent by the target height (r = 0.53).

CONCLUSIONS

The therapeutic dose is the decisive parameter for prediction of the therapeutic effect of growth hormone in children with growth hormone deficiency. It is justified to modify the therapeutic dose individually with regard to the initial characteristic and therapeutic target of every given patient.