PT - JOURNAL ARTICLE AU - Hasanbegovic, Snijezana AU - Tihic-Kapidzic, Suzana AU - Begovic, Ermin AU - Hasanbegovic, Snijezana TI - PP-020 The effect of substitution of vitamin D in children under growth hormone therapy – absolute deficiency AID - 10.1136/bmjpo-2024-EPAC.164 DP - 2024 Jul 01 TA - BMJ Paediatrics Open PG - A73--A73 VI - 8 IP - Suppl 5 4099 - http://bmjpaedsopen.bmj.com/content/8/Suppl_5/A73.2.short 4100 - http://bmjpaedsopen.bmj.com/content/8/Suppl_5/A73.2.full SO - BMJ Paediatrics Open2024 Jul 01; 8 AB - Aim Vitamin D and growth hormone (GH) are synergists in creating healthy, strong and adequately long bones. Vitamin D deficiency is present in up to 80% of children. To compare the average growth in body height in the first year of GH therapy in pediatric patients with GH deficiency without and with adequate vitamin D substitution.Material and Method The diagnosis of absolute deficiency of GH was established by a stimulation test with insulin hypoglycemia with a cut-off value of 10 µg/L. In the first group, vitamin D was not administered or substituted before the start of GH therapy, and in the second vitamin D was determined by the immunoassay method of patients and substituted to reference values (>30 ng/ml) before the start of GH therapy.Results The average dose of GH for both groups was 0.034 mg/kg/day. GH therapy was started immediately for 28 patients (15M/13F), the average increase in height after first year of therapy was 10.5 cm. In the second group of patients 31 (17M/14F), only 20% of the children had vitamin D in the reference range, and the mean was 14.9 ng/ml, after 2 months D vitamin it was substituted to mean of 39 ng/ml and GH was started. The average height increase in body height in the first year of therapy for this group was 11.9 cm (p < 0.05).Conclusions Before the start of HR therapy, determining the level of vitamin D and substituting it in a short time to the reference values is important fot a significantly greater increase in body height in the first year of growth hormone therapy in patients with absolute deficiency and achieving better results of therapy in general.