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Endocrine Abstracts (2024) 99 P13 | DOI: 10.1530/endoabs.99.P13

1University of Birmingham, UK; 2MRC Laboratory of Medical Sciences, UK; 3University Hospital Würzburg, Würzburg, Germany; 4University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 5amedes experts, Hamburg, Germany; 6Newcastle University, UK; 7The University of Sheffield, UK; 8Cardiff University, UK; 9Klinikum der Universität München, München, Germany; 10Ludwig Maximilian University of Munich, München, Germany; 11Diurnal, UK


Background: Primary adrenal insufficiency (PAI) is rare: prevalence ~100–140/million and incidence 4:1 000 000/year in Western societies 1. The diagnosis of PAI is suggested by an early-morning cortisol <140 nmol/l (5 μg/dl) 1. The commonest cause in adults is autoimmunity (~90% in Western countries) and it is generally considered progressive once the diagnosis is made, although it has been reported that residual cortisol secretion is present in ~30% of patients 2. We have developed a modified-release formulation of hydrocortisone to replace the physiological cortisol circadian rhythm and are undertaking a Double-Blind, Double-Dummy, Two-Way Cross-Over, Randomised, Phase II Study of Modified-Release Hydrocortisones: Chronocort® Versus Plenadren®, in PAI. During recruitment, we were surprised by the number of patients who were ineligible as they had detectable morning cortisol levels.

Methods: Main inclusion criteria: Participants with known PAI on stable glucocorticoid replacement therapy and an early morning pre-dose cortisol <50 nmol/l (1.8 μg/dl). Baseline serum cortisol was taken at ~0700 h and measured in a central laboratory by ADVIA Centaur® immunoassay with the lower limit of detection <14 nmol/l (<0.5 μg/dl).

Results: 86 patients with PAI (autoimmune aetiology in 71), median age 52 years (range 20–73), 60 female, were screened in 8 centres in UK and Germany. 18 (21%) patients were excluded from the study based on morning cortisol >50 nmol/l (1.8 μg/dl), and of those 68 patients who qualified on the main inclusion criteria 51 (59% of screened) had a cortisol <14 nmol/l (<0.5 μg/dl). Of the 18 patients (autoimmune aetiology in 10) excluded based on their morning cortisol level, 9 (50%) were female and 11 (13% of screened), had morning cortisol ≥140 nmol/l (5.0 μ/dl). 12 patients with morning cortisol of >50 nmol/l (1.8 μ/dl) were retested and only 2 then qualified; their initial morning cortisol levels were 70 and 51 nmol/l. In patients retested the median difference between retest and the initial sample was 13 nmol/l (range 1–421 nmol/l).

Conclusions: In patients with an established diagnosis of PAI, the majority had undetectable morning cortisol, but cortisol was detectable in 41% of patients and above 140 nmol/l in 13% confirming previous publications 2. Retesting patients with a cortisol >50 nmol/l showed very similar results suggesting that the detectable cortisol was not an artefact and likely due to background cortisol secretion.

References: 1. Bornstein SR, et al. J Clin Endocrinol Metab 2016;101:364–89.

Volume 99

26th European Congress of Endocrinology

Stockholm, Sweden
11 May 2024 - 14 May 2024

European Society of Endocrinology 

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