ESPE Abstracts

Background: Although it has been recommended to start treatment in the range of 22-35 µg/kg/day in growth hormone (GH) deficiency, individualized dose selection is more preferred for those patients instead of a fixed dose. However, there is no consensus as to which dose should be started for which patient. In this study, we aimed to reveal the factors that affect the clinicians' preferences in the selection of the starting dose of GH treatment.

Methods: Patients aged <18 years, who applied to our department between 2013 and 2022 and were diagnosed with isolated GH deficiency and started treatment, were included in the study. Relevant data were collected retrospectively from the medical records of the patients. Results are presented as median (25-75p).

Results: Eighty-eight patients (56.8% male; 65.9% prepubertal) with a calendar age (CA) of 10.4 (7.4-12.8) years were included in the study. The median bone age (BA) of the cases was 8 (5-10) years and height standard deviation score was -2.7 [(-3.3) – (-2.3)]. Somatropin treatment was started at a median dose of 35 (30-35) µg/kg/day. Patients were divided into two groups according to the treatment dose as <35 µg/kg/day (n=36) and ≥35 µg/kg/day (n=52). The target height was shorter (P=0.033) and the annual height velocity was lower (P=0.008) in the group in which high-dose treatment was initiated. While the ratio of BA/CA was similar in both groups (P=0.730), the difference between BA - CA was significantly higher in the high-dose given group (P=0.018). Other anthropometric measurements, peak response in GH stimulation tests, serum IGF-1 and IGFBP-3 levels did not differ among the two groups (P>0.05). The initial dose of somatropin correlated negatively with annual growth rate (P=0.006), positively to the difference between BA - CA (P=0.009).

Conclusions: In this study, we found that target height, annual growth rate, and the difference of BA - CA were taken into account in the selection of the initial treatment dose in children diagnosed with isolated GH deficiency. We demonstrated that those who were started on high-dose treatment had lower growth rates and more retarded BA. Also, we found that the peak response in stimulation tests or baseline IGF-1 and IGFBP-3 levels were not effective in the initial treatment regimen choices. This result showed that clinical findings rather than laboratory parameters were taken into consideration by clinicians for somatropin treatment dose preferences in children.