A-072 Growth hormone stimulation tests: experience of a large cohort from a Brazilian diagnostic medical center

Abstract Background Growth hormone (GH) stimulation tests are used to diagnose short stature in children and to assess hypothalamic-pituitary axis in adults. The most frequently stimulation tests are: oral clonidine (CLO), insulin-induced hypoglycemia (ITT), glucagon (GLU) and exercise (EXE). Well-known side effects are hypotension, nausea and vomiting. The aim of this study was to evaluate side effects and intercurrences observed during the performance of GH stimulation tests and to identify their possible predisposing factors. Methods From April/2022 to May/2023, in a large private laboratory located in 8 different sites, 3,006 GH stimulation tests were performed, with 266 patients with two or more GH stimulation tests. Results Considering only patients aged < 18 years (95% of the tests), the mean age was 10.3 ± 2.7 years (median 10.6 years), with 62.5% being male. GH stimulation test was distributed as follows: 64% CLO, 27.6% ITT, 7% GLU and 1.4% EXE. Patients with a history of asthma, allergies, seizure and heart disease were reported in 3%, 1.7%, 0.9% and 0.6%, respectively. More than 2 punctures for venous access were necessary in 9.3% of the cases, particularly in CLO test. The age of patients submitted to GLU was significantly lower compared to CLO and ITT (9.5 ± 3.3 years vs 10.3 ± 2.7 years and 10.6 ± 2.6 years, p < 0.001). Side effects were noted in only 5.1% of the total tests (145/2,863 tests), most frequent in the GLU (50/197 tests, 25%) and none observed in the EXE. There was no correlation of reported side effects with age and weight. As expected, hypotension was more frequent in CLO (27%), not associated with the oral clonidine administered dose (0.1 or 0.150 mg/SC). Nausea and vomiting occurred in 23% of the GLU tests. Symptomatic hypoglycemia that needed glucose administration (oral or parenteral) occurred in 8% of the ITT. Cough was observed in 6 patients during CLO, with no previous history of asthma or allergies. There were no occurrences that hospital transfer was need. Conclusions GH stimulation tests are safe and rarely cause serious side effects, certainly due to the presence of a prepared team for promptly support.