Determinants of Final Height in Patients Born Small for Gestational Age Treated with Recombinant Growth Hormone

Introduction: About 8% of children born small for gestational age (SGA) do not reach a final height within the normal range. Recombinant human growth hormone (rhGH) has been shown to be effective in increasing the final height in children born SGA. Our objective was to identify predictive factors of final height in children born SGA treated with rhGH.

Materials and methods: In this retrospective study, conducted in a tertiary pediatric endocrinology referral center, we recruited all patients born SGA (defined as birth length or weight <10th percentile) treated with rhGH for more than 12 months for whom final height data were available. Some patients had received gonadotropin-releasing hormone (GnRH) analog therapy.

Results: We included 252 patients with an average birth length of -2.0 ± 0.7 SD and birth weight of -1.7 ± 1.0 SD. After 4.6 ± 2.8 years of rhGH treatment, their height increased from -2.2 ± 0.9 SD to -1.5 ± 0.9 SD. In multivariate analysis, we identified 8 factors that predict 46% of the final height, namely, cause of SGA (p < 0.0001), GnRH analog therapy >2 years (p = 0.006), birth length (p < 0.02), height at the start of rhGH (p < 0.0001), IGF-1 level at the start of rhGH (p = 0.0002), growth velocity during the 1st year of treatment (p = 0.0002), and age and height at the onset of puberty (p < 0.0001, p = 0.0007, respectively).

Conclusion: In this large cohort of SGA patients who had reached their final height, we were able to confirm that growth hormone increases final height in short SGA children. In addition, we identified several factors associated with a better response to growth hormone treatment.