Endocrine Abstracts

Introduction: Although possible autonomous cortisol secretion (pACS) is the commonest endocrine dysfunction detected in patients with adrenal incidentalomas, the diagnosis of this condition is still challenging. Dehydroepiandrosterone sulfate (DHEAS) is an adrenal androgen secreted by adrenal glands under the regulation of ACTH. DHEAS does not follow a circadian rhythm and has a long half-life in serum. Because of these features, low blood concentration of DHEAS has been recently investigated as a screening marker of pACS. Nevertheless, data regarding the diagnostic accuracy of DHEAS to predict pACS are sparse and contradictory.

Methods: 74 patients with adrenal incidentalomas were evaluated in the context of ERGO trial (NCT02611258). Clinical, hormonal and radiological assessment were performed to exclude Cushing’s syndrome, pheochromocytoma, Conn syndrome, adrenocortical carcinoma, late-onset congenital adrenal hyperplasia, myelolipoma and metastasis. Cortisol levels after a 1-mg overnight dexamethasone suppression test between 51 and 138 nmol/l, confirmed by 48-h Liddle tests, were used to classify patients as pACS. DHEAS ratios were calculated by dividing the DHEAS by the lower limit of the respective reference range according to age and gender.

Results: 36 patients were diagnosed with adrenal adenoma associated with pACS (pACS group) and 38 with non-functioning adrenal adenoma (NF control group). There were no difference in age (pACS: 65.8±11.3 years; NF: 64.03±11.0 years; P=0.560), body mass index (pACS: 27.71±5.5 kg/m²; NF: 27.8±4.2 kg/m²; P=0.942), and sex (pACS: female 23/31; NF: female 17/33; P=0.110) between the two groups. Mean DHEAS ratio was significantly lower in the pACS compared to the NF group (pACS: 1.24±1.55; NF: 2.68±0.86; P<0.001). Furthermore, there was a negative correlation between the post-dexamethasone cortisol levels and DHEAS ratio (r=−0.382; P=0.002). ROC analyses [AUC 0.837 (0.737–0.936); P<0.0001], showed that a DHEAS ratio of 1.56 suggested a sensitivity of 81% and specificity of 71% for the diagnosis of pACS with a positive predictive value of 73.5%, a negative predictive value of 78.6% and reaching an accuracy of 75.8% in predicting pACS.

Conclusion: Our study shows that DHEAS ratio may contribute to the diagnostic work-up in patients with adrenal incidentalomas. A single basal measurement of age and gender-adjusted DHEAS ratio could be included as an advantageous screening test for the detection of possible autonomous cortisol secretion. Further studies are needed to confirm the role of DHEAS screening in the diagnostic evaluation of pACS.