Endocrine Abstracts

Backgound: Adrenal incidentalomas (AI) are lesions that are incidentally identified while scanning for other conditions. The European Society of Endocrinology guidelines recommend that all patients with AI should undergo an overnight dexamethasone suppression test (ONDST) for the evaluation of autonomous cortisol secretion as defined by failure of suppression of cortisol to < 50 nmol/l. The reported prevalence of this is high (50% of patients in a recent publication) and may be linked to an increase risk of cardiometabolic complications in these patients. The ONDST requires attendance to a health care facility and venepuncture. Cortisol and cortisone measurements can also be taken on salivary samples which can be easily collected and posted to the laboratory offering convenience to the patient. We therefore aimed to assess the utility of these measurements in patients with AI.

Methods: We retrospectively analysed the data of 112 patients with AI who underwent an ONDST with measurement of post dexamethasone (0900 h) serum cortisol and salivary cortisol and cortisone and serum and salivary cortisol and salivary cortisone at around midnight the night before. Both serum and salivary samples were analysed with liquid chromatography-tandem mass spectrometry. Statistical analysis was done using SPSS.

Results: There were 64 female and 48 male patients mean age 64, 31 with bilateral adenomas. 48 (43%) failed to suppress there cortisol to < 50 nmol/l. There was a strong correlation between salivary cortisone and serum cortisol post 1 mg dexamethasone (R² Linear 0.907). No correlation was observed between, serum and salivary cortisol post dexamethasone, or midnight salivary cortisol and cortisone and serum cortisol post dexamethasone.

Discussion: In an ONDST for AI patients, post dexamethasone, salivary cortisone correlates very strongly with serum cortisol and could therefore be used as an alternative sampling method in the ONDST as a simple test (when available) for the evaluation of cortisol secretions in patients with AI which does not require venepuncture or attendance to hospital. We have demonstrated that the prevalence of autonomous cortisol secretion in patients with AI is high and is in line with data that has been reported in the literature recently.