Objective: The glucagon stimulation test (GST) is a well-tolerated test to assess growth hormone deficiency (GHD) in patients with hypothalamic-pituitary disorder. One reported complication of GST is hypoglycemia. This retrospective study aims to assess the prevalence of hypoglycemia during GST and the associated patient characteristics that may increase the risk of hypoglycemia.

Methods: The GSTs performed between 2019 to 2024 were retrospectively analysed. Patient information such as demographics, age, comorbidities, underlying pituitary disease and results of GST were documented. The development of hypoglycemia, defined as blood glucose level (BGL) below 4 mmol/L, and associated symptoms were recorded.

Results: Of the 47 patients who underwent GSTs between 2019 to 2024, the prevalence of hypoglycemia was 61.7% (N = 29). 12 (25%) had BGL between 3.1-3.5 mmol/L while 8 (17%) had severe hypoglycemia of BGL 3.0 mmol/L or less. Only 6% of patients (N = 3) had mild symptoms of hypoglycemia. Two patients received stress dose oral hydrocortisone 20 mg; however, despite this, one patient who had two pituitary hormone dysfunction (excluding cortisol) experienced hypoglycemia with nadir BGL 2.9 mmol/L. Only two patients were not diagnosed with GH deficiency. We did not identify any specific variables that increased the risk of hypoglycemia during glucagon stimulation test.

Conclusion: Whilst the prevalence of hypoglycemia with glucagon stimulation may be high, majority of the patients were not symptomatic with hypoglycemia. It is unclear whether pre-treatment with stress dose hydrocortisone prevents hypoglycemia. However, careful monitoring of BGLs during testing and treating hypoglycemia if it occurs remains a priority.