Impact of Daily Growth Hormone Adherence on Height Velocity Among Children With Growth Hormone Deficiency (GHD)

Objective: To describe adherence to daily somatropin treatment and impact on height velocity within 1 year of treatment start among patients with pediatric growth hormone deficiency in a real-world US population. Methods: This retrospective cohort study included pediatric patients aged ≥3 years to <16 years with pediatric growth hormone deficiency prescribed somatropin by a pediatric endocrinologist at a US-based center of excellence between January 1, 2015 and December 31, 2020. Patient data were collected using hospital electronic health records linked to a specialty pharmacy patient prescription records. Adherence, evaluated over 12 months, was measured using the proportion of days covered metric and patients were categorized as adherent if their proportion of days covered ≥80%. Height velocity was annualized to compare across adherent and nonadherent patients. Results: One hundred eighty-one patients were identified and included in this study, of which 70.2% were male,73.5% were white, and mean age (standard deviation [SD]) at index was 12.1 (2.8). In the height velocity analysis, 174 patients were included and the mean (SD) annualized change in height was 10.2 (5.7) cm/y in the adherent group (n = 108) and 9.8 (7.6) in the nonadherent group (n = 66). The difference in height velocity between the groups was not statistically significant. Conclusions: Minor improvements in average height velocity were observed in the patient group who were adherent to somatropin therapy, although not statistically significant. Lack of observed significance may be due to small sample sizes, short observation period, a likely heterogenous population in terms of growth hormone prescribing, data bias due to single-center origin, or potential patient misclassification.