Human Growth Hormone and Gonadotropin Releasing Hormone Analog Combination Therapy Increases Predicted Height in Short Normal Girls

Abstract

The “short normal” child constitutes a real challenge for the pediatric endocrinologist. In a subgroup of short normal children, puberty starts at a normal age but with low height, and hence, the final height is expected to be quite compromised. Efforts to improve the outcome in this group have been made in the past with equivocal results. We present the growth data of 8 short girls with normal growth hormone values on provocative testing and low height at puberty initiation. At intervention the height and the stage of puberty were 129.3 ± 5 cm and II to III, respectively, and the predicted height was 148.8 ± 2.6 cm. Gonadotropin releasing hormone analog, triptorelin (3.6 ± 0.5 pg/kg/day) and growth hormone (0.5 IU/kg/week) were used in different sequential order and simultaneously in each child. The mean total treatment period was 47.6 ± 11.2 months. The mean predicted and the mean final height in the total group were 148.8 ± 2.6 and 154.5 + 3.6 cm, respectively (p:0.028). The final height did not differ from the target height (154.8 ± 8 cm versus 154.5 + 3.6 cm), while in 4 children, the final height was greater than the target height. The height gain (Δ Final height Predicted height) was 5.7 ± 1.3 cm. If we analyze separately the girls in whom growth hormone was started first and gonadotropin releasing hormone analog followed versus those who started the analog first, the Δ Final height Predicted height was 8 ± 3 cm in the former and 4.8 ± 3.1 cm in the latter (p:0.03). It seemed that the difference was accounted for by duration of growth hormone therapy (51.3 ± 10.6 months versus 28.6 ± 10.6 months) (p:0.026), rather than by other factors. In conclusion, under the conditions of the present study, the combination of puberty arrest and growth hormone therapy significantly improved predicted height. The most significant determinant of the height gain was the duration of growth hormone therapy.