Long-term response to recombinant human growth hormone therapy in Indian children with growth hormone deficiency

Abstract

Background: Growth hormone deficiency (GHD) remains the most common indication for use of recombinant human growth hormone (rhGH) therapy in clinical practice. However, there is a paucity of studies focusing on long-term response to rhGH therapy in the Indian context. Aim: To determine the response to rhGH therapy and its predictors in children with GHD followed up at a tertiary care center in North India. Materials and Methods: We performed a retrospective review of the records of children with GHD who received rhGH therapy for at least 1 year. The relevant anthropometric, biochemical and radiological data at baseline and follow-up were recorded. Results: A total of 99 children (64 boys, 35 girls; 61 isolated GHD, 38 multiple pituitary hormone deficiency) were studied. The mean (±SD) age and height SDS at treatment initiation were 12.4 (±3.0) years and -4.0 (±1.1) respectively, while median (IQR) serum insulin-like growth factor 1 (IGF-1) and peak growth hormone level on clonidine stimulation were 73 (25-167) ng/ml and 1.1 (0.4-3.6) ng/ml respectively. The height velocity was highest during the first year of treatment (10.6 ± 3.0 cm/year), declining to 8.7 ± 2.7 and 7.9 ± 2.2 cm/year during second and third year, respectively. Over the subsequent years, there was further graded fall in height velocity, declining to 4.8 ± 3.6 cm/year (n = 2) during the seventh year. The height gain during first year was negatively correlated with age at initiation of treatment, baseline height SDS, baseline serum IGF-1 and peak serum GH level on GH stimulation test, while it showed a positive correlation with bone age delay at baseline. Only baseline height SDS was found to have a significant negative correlation with height gain during the second year. Conclusions: This study provides data on long-term response to rhGH therapy and its predictors in Indian children with GHD.