Growth hormone treatment regimens in girls with Turner syndrome. Dutch Advisory Group on Growth Hormone.

To optimize growth hormone (GH) treatment in girls with Turner syndrome, two multicentre studies were carried out in The Netherlands: a frequency-response study (study 1) and a dose-response study (study 2). In study 1, 19 girls with Turner syndrome, aged 11 years or older, were treated with one or two daily injections of GH at a total dose of 6 IU/m2/day (0.067 mg/kg/day) and ethinyloestradiol given orally at a dose of 0.05 microg/kg/day. All the girls reached final height. The mean (+/-SD) gain in final height was not significantly different between the once- or twice-daily regimens (7.6 +/- 2.3 versus 5.1 +/- 3.2 cm, respectively). The mean final height attained was 155.5 +/- 5.4 cm. All the girls exceeded their adult height prediction. In study 2, 68 girls with Turner syndrome, aged 2-11 years, were randomized into three dosage groups: A, B and C. During the first year, the girls in all the groups received GH at a dose of 4 IU/m2/day (0.045 mg/kg/day), which group A continued to receive throughout the study. At the start of the second year, groups B and C were switched to a dose of 6 IU/m2/day, which the girls in group B continued to receive for the remainder of the study. At the start of the third year, the girls in group C were switched to a dose of 8 IU/m2/day (0.090 mg/kg/day) for the remainder of the study. After 7 years of GH treatment, height SDS (based on Turner syndrome and normal population references) increased significantly in all three groups, but significantly more in groups B and C compared with group A (p = 0.02 and p = 0.001, respectively). Predicted adult height increased significantly, without a significant difference between the three dosage groups. The mean final heights of 25 of the girls were 159.1, 161.8 and 162.7 cm for groups A, B and C, respectively.