ECE2022 Poster Presentations Pituitary and Neuroendocrinology (127 abstracts)
University of Turin, Department of Medical Science, Division of Endocrinology, Diabetes and Metabolism, Turin, Italy
Introduction: The diagnosis of GH deficiency (GHD) in adults is based on a reduced GH response to provocative tests. The proportion of patients with low GH response to provocative tests increases with the number of other pituitary hormone deficiencies and several studies involving panhypopituitary patients have shown that under certain circumstances GH stimulation tests may be unnecessary to diagnose GHD.
Objective: Aim of this study was to re-evaluate the diagnostic cut-offs of GH response to GHRH + arginine (ARG) test in function of BMI. To this aim the patients pituitary function was considered as the gold standard for the diagnosis or exclusion of GHD; in particular GHD was defined by the presence of at least 3 others pituitary deficits, while a preserved somatotropic function was defined by the lack of others pituitary deficits.
Methods: The GH responses to GHRH + ARG were studied in 349 patients with history of hypothalamic-pituitary disease [age (mean ± SD): 43.8 ± 16.5 years; BMI: 27.4 ± 9.2 kg/m2 ]. Patients were divided into lean (143), overweight (107) and obese (99) subjects according to BMI. The best GH cut-off to GHRH + ARG, defined as the one with the best sensitivity (SE) and specificity (SP), was identified using the receiver-operating characteristic curve (ROC) analysis.
Results: The best GH cut-off to GHRH + ARG was 5.5 μg/l in lean subjects (SE 89.2%, SP 79.7%), 4.2 μg/l in overweight subjects (SE 94.0%, SP 62.5%) and 2.8 μg/l in obese subjects (SE 85.7%, SP 83.3%). The diagnostic accuracy was 85.3, 82.2 and 84.8% respectively.
Conclusions: To our knowledge this is the first study that evaluate the diagnostic cut-offs of GH response to GHRH + ARG in function of BMI using a clinical definition of GHD as gold standard. Our results suggest that with this new approach, the GHRH + ARG cut-offs should be revised.