Prediction of First-Year Growth Velocity Response to Growth Hormone Therapy in Patients with Growth Hormone Deficiency.

INTRODUCTION: First-year growth response to biosynthetic growth hormone (GH) largely varies between populations. We aimed to predict first-year growth response to growth hormone replacement therapy (GHRT) in children with growth hormone deficiency (GHD). METHODS: Growth response during the first year of GHRT was determined for both prepubertal and peripubertal children with congenital isolated GHD. The diagnosis of GHD was made using a standard work-up plan. Subjects with acquired causes of GHD were excluded. GHRT was started as per standard treatment guidelines. A predictive growth model based on these variables was derived from the analysis for the first-year growth response. RESULTS: A total of 107 children with congenital GHD were studied (70 prepubertal; 37 peripubertal). The age at initiation of GHRT was 11.36 ± 3.83 years. In the prepubertal group, age at baseline and differences between mid-parental height (MPH; MPH-standard deviation score [SDS] and height-SDS) were significant predictors of first-year growth velocity response. The first-year height velocity was 11.12 ± 3.62 cm. Prediction formula for prepubertal group is as follows: first-year growth velocity = 10.24 + 1.27*(difference between MPH-SDS and height-SDS) -0.27* Age. In peripubertal children with GHD, gender, mother's height, and the difference between MPH-SDS and height-SDS were important predictors of first-year growth velocity. The first-year height velocity was 8.85 ± 2.84 cm. Prediction formula for the peripubertal group is as follows: 14.09 + 0.69*(difference between MPH-SDS and height-SDS) + 0.16*Mother height-2.51*gender. CONCLUSION: This model is an accurate and practicable tool to predict first-year growth response in GHD children in the Indian subcontinent.