ESPE Abstracts

Introduction: About 15% of children born small for gestational age (SGA) do not reach final height within normal range. Recombinant human growth Hormone (rhGH) has shown to be effective in catching up growth velocity and height in children born SGA.The objective of our study is to identify the predictive factors of final height in children born SGA treated with rhGH.

Materials and Methods: Monocentric, retrospective study in a tertiary pediatric endocrinology referral center. We included all patients older than 16 years, born SGA defined as birth length or weight <10^th centile and treated with rhGH for more than one year. Patients treated with GnRH analogues (GnRHa) were included. Patients treated with aromatase inhibitors were excluded.

Results: 255 patients were included [98 boys, 157 girls]. 120 patients received GnRH analogues for precocious or advanced puberty and advanced bone maturation. They had an average birth length of -2.0±0.7 SD and birth weight of -1.6±1.0 SD. Upon 4.5±2.8 years of rhGH treatment, height increased from -2.2±0.9 to a normal height of -1.5±0.9 SD. The target height of this population was -0.8±0.8 SD.

Our multivariates analysis identified 8 factors that predict 46 % of the final height including SGA causes (R²=10%, P <0.0001), treatment with GnRHa > 2 years (R²=0.1%, P=0.006), birth length (P<0.02, R²=4%), height at start of rhGH (R²=5%, P<0,0001), IGF1 at start of rhGH treatment (R²=8%, P=0.0002), growth velocity during the first year of treatment (R²=8%, P=0.0002), age at onset of puberty (R²=5%; P<0,0001) and height at onset of puberty; (R²=4%, P=0,0007).

Furthermore, the better response to rhGH was associated to the absence of chromosomic abnormalities or bone malformations (P=0.0003), to mother's height -height between -1 SD and 0 SD (P= 0.02), to a great growth velocity at one year of treatment (OR = 1.3 [1.1-1.6], P=0.004), to an extended time on treatment (OR =1.6 [1.3-1.9], P<0.0001) to a low IGF1 (OR=0.4 [0.2-0.6], P<0.0001), to a late pubertal development, or to short stature associated to puberty (OR = 1.9 [1.4-2.5], P<0.0001; OR = 0.6 [0.4-0.9],P= 0.03).

Conclusion: In this large cohort of patients who achieved their growth we were able to identify several factors influencing the final height and the response to growth hormone therapy in children born SGA. This will likely help the management of rhGH in the future for this specific target population.