BSPED2023 Poster Presentations Adrenal 2 (8 abstracts)
1School of Clinical Medicine, University of Cambridge, Cambridge, UK; 2Weston Paediatric Endocrinology and Diabetes Clinic, Cambridge University Hospital NHS Foundation Trust, Cambridge, UK; 3Department of Blood Sciences, Cambridge University Hospital NHS Foundation Trust, Cambridge, UK
Background: The short synacthen test (SST) is commonly used to evaluate the integrity of the hypothalamicpituitaryadrenal (HPA) axis in children. However, this test is time-consuming, requiring cannulation, several blood samples, and medical observation. Studies in adults have suggested an early morning serum cortisol level could be used to rule out or confirm adrenal insufficiency, reducing reliance on SSTs, however, few studies have evaluated this in children.
Objectives: To define an assay-specific morning cortisol level able to predict adrenal sufficiency in children.
Methods: This was a retrospective single-centre study of SSTs performed at a tertiary paediatric endocrine clinic from January 2020 to May 2023. Tests included were those in children and young people aged 28 days to 18 years old, where an early morning serum cortisol level was collected between 0800 and 1000 hours. Cortisol was measured by Siemens Immunoassay (Centaur and Atellica). A peak serum cortisol of ≥450 nmol/L was considered an adequate response to stimulation to rule out adrenal insufficiency. Receiveroperator curve (ROC) analysis was used to determine early morning cortisol levels that could rule out or confirm adrenal insufficiency.
Results: A total of 81 tests were included from 76 children and young people (aged 4 months to 17 years, 43% female). Adrenal insufficiency was diagnosed in 17 (21%) of our patients, based on SST results. ROC analysis revealed that an early morning cortisol of ≥292 nmol/L had 100% specificity to rule out adrenal insufficiency, and a level of <114 nmol/L could confirm adrenal insufficiency with 100% specificity. By performing SSTs only in young people with early morning cortisol levels between these two cut-offs, in our centre we could avoid 41% of SSTs.
Conclusions: We propose that early morning cortisol levels represent a valid tool for the initial assessment of adrenal function in children and young people with the potential to obviate a substantial number of SSTs.