Determinants of early growth response to recombinant growth hormone therapy in children with isolated growth hormone deficiency

Growth hormone deficiency (GHD) is an important endocrine cause of short stature in childhood, occurring in approximately 1 in 4,000–10,000 live births. Early diagnosis and treatment are critical for achieving optimal height growth. This study was designed to identify factors influencing early growth response to recombinant human growth hormone (rhGH) treatment in children with isolated growth hormone deficiency (IGHD). This retrospective study included data from 205 patients diagnosed with IGHD who received rhGH treatment for at least one year at the pediatric endocrinology clinic of a tertiary children's hospital between 2009 and 2013. Isolated GHD was defined as cases meeting auxological criteria and having a peak GH response <10 ng/mL on two different GH stimulation tests. Patients were grouped into good and poor treatment response categories based on the change in height standard deviation score (Δ height SDS) during the first year of treatment. Demographic characteristics, anthropometric measurements, GH stimulation test results, serum IGF-1 and IGFBP-3 levels, pituitary magnetic resonance imaging (MRI) findings, bone age, and trace element levels were evaluated. The mean age at diagnosis was 10.5±2.9 years, and a good response to treatment was observed in three-quarters of the patients (74%). Pituitary MRI findings were not significantly associated with treatment response. Younger age at diagnosis, a lower peak GH response at diagnosis, and higher IGF-1 SDS after one year of treatment were associated with a better first-year growth response to rhGH therapy. Abbreviations: GH: Growth Hormone, GHD: Growth Hormone Deficiency, IGHD: Isolated Growth Hormone Deficiency, IGF-1: Insulin-like Growth Factor-1, IGFBP-3: Insulin-like Growth Factor Binding Protein-3, rhGH: Recombinant Human Growth Hormone, MRI: Magnetic Resonance Imaging, SDS: Standard Deviation Score