Factors influencing growth in children with growth hormone deficiency – a case-control study

Introduction
To assess the response of South Indian children with growth hormone deficiency (GHD) to growth hormone therapy, optimal duration of therapy for good catch up, and factors determining the response of our children to growth hormone therapy.

Material and methods
We conducted a case control study at a paediatric endocrine unit of a tertiary paediatric hospital. Children diagnosed with growth hormone deficiency were initiated on GH (cases) or followed up without GH therapy (controls). Detailed clinical, biochemical, radiological, and treatment parameters were recorded at baseline and follow-up. Data were analysed using IBM SPSS version 21.

Results
We enrolled 23 subjects in group I (cases who received GH) and group II (controls with untreated children), and both the groups were comparable at baseline. Group I (–4.12 ±1.7 to –2.81 ±1.52) had significant height increase on follow-up after GH therapy compared to group II (–3.55 ±1.7 to –3.51 ±1.52) (p > 0.05). Growth velocity in group I (13.25 ±5.6 cm/year, SD score 4.55 ±5.42) was significantly higher compared to group II (3.4 ±1.8 cm/year, SD score –1.62 ±2.38). Duration of growth hormone therapy, presence of ectopic posterior pituitary, and BA: CA ratio independently impacted the growth velocity SD scores. Kaplan Meier analysis curve showed 15 months of GH therapy was needed to attain a height within ±2 SD of the target height.

Conclusions
Early diagnosis, pre-pubertal status, delayed bone age, and presence of ectopic posterior pituitary on MRI are determinants of a better response. Growth hormone must be administered for at least 15 months for catch up height SDs within target height SD range.