IMPE Abstracts

Background: There are limited studies of growth and growth velocity (GV) after discontinuation of GnRHa in ICPP girls. Controversy exits about the growth after GnRHa especially regarding age of onset/end of treatment and onset of menses.

Objective: To evaluate growth after GnRHa discontinuation up to final height (FH) by growth velocity analysis (GV), time of menarche (TM) and change of standard deviation of height for bone age (H-BA-SD) during treatment.

Methods: Retrospective and analytical study. We included 100 girls with ICPP diagnosis > 4 years of chronological age (CA), followed every 6 months from discontinuation of GnRHa up to FH. Target height (TH), bone age (BA) at onset and end of treatment, age of menarche and auxologiocal data up to FH were registered. H-BA-SD was calculated by Auxology program employing Argentinian reference tables. Data are expressed as mean ± SD.

Results: At GnRHa onset CA was 7.8 ± 1 years and BA-CA 2.3 ± 1 years. After 2.6 ± 1.1 years of treatment, CA at end of treatment was 10.5 ± 0.4 years and BA-CA 1.5 ± 0.7 years. During treatment patients gained 0.4 ± 0.8 H-BA-SD (P<0.0001). H-BA-SD gain was significantly associated to growth between aGnRH onset up to FH (r=0.50, P<0.0001). The H-BA-SD at the end of treatment was strongly associated with FH-SD (r=0.8, P<0.0001). Growth after GnRHa discontinuation was 12.7 ± 3.1 cm. GV was 5.8 ± 1.5, 5.9 ± 1.7, 4.9 ± 1.7 and 3.8 ± 1.7 cm/year at 6, 12, 18 and 24 months, respectively (ANOVA, P<0.01). Menarche occurred at CA 11.7 ± 0.8 years, after 1.2 ± 0.7 years of GnRHa withdrawal. Growth after GnRHa discontinuation was not associated with time of menarche, however, was lower in patients with BMI > 2 SD at start treatment (11 ± 3 cm, P<0.05). FH–TH was 1.42 ± 5.2 cm and 99 % of girls reached TH.

Conclusion: Our results confirm the effectiveness of treatment with GnRHa on growth during and after treatment in ICPP girls, allowing them reach TH and present menarche at a normal age according to Argentinian references. The growth after treatment discontinuation was not affected by time of menarche although shorter in patients with obesity at onset of GnRHa. The most important predictor for final height was the H-BA-SD at the end of treatment. These data help EndoPed better estimate potential height outcome especially regarding timing of discontinuation of GnRHa treatment.