Growth and Final Height in Girls with Central Precocious Puberty after Long-term Treatment with Depot Gonadoliberin Analogue

Overview

Objective:
Analysis of the growth and factors influencing the final height in girls with central precocious puberty (CPP), treated with a gonadoliberin analogue.

Type of study (design):
A long-term open clinical study.

Methods:
Ten girls with CPP, six of them with idiopathic (ICCP) and four with organicallybased (OCPP) form, respectively, were treated for the period of 3.9±0,9 y (mean ± S.D.) (range 2.6–6 years) with a depot agonist of gonadoliberin containing the active molecule of triptorelin.

The final or almost final height was compared with expected body height acccording to parents (hereditary growth potential) and with a growth prognosis (determined by the projection method) during establishing the diagnosis, at the end of therapy and at menarche. Factors related to final body height were analyzed.

Results:
The girls reached final body height of 160.5 ± 6.9 cm, less than the expected height according to their parents (166.0 ± 5.3 cm) (p = 0,03). Their growth potential was already decreased at the beginning of therapy and improved only insignificantly since then. The height prediction at the time of menarche (162.3 ± 5.4 cm) did not differ from the final height reached (NS). Significant relations were demonstrated between the final height and age at the beginning of treatment (r = -0.7), the bone age before the end of therapy (r = -0.7) and the growth rate in the first year after the end of therapy (r = 0.7). The higher growth rate in the first year after treatment was observed in girls with a lower bone age at the end of therapy (r = -0.8). The bone age below 12 years appeared to be optimal for cessation of therapy in our group.

Conclusion:
Girls who were younger at the beginning of therapy with gonadoliberin therapy reached higher final height. A timely cessation of the therapy with a gonadoliberin analogue at the bone age of 12 years at the latest proved to be the significant factor for reaching the final height in agreement with the hereditary growth potential.

Key words:
central precocious puberty, growth, final body height, treatment, gonadoliberin agonist