Accuracy of the dexamethasone suppression test for the prediction of autonomous cortisol secretion-related comorbidities in adrenal incidentalomas

Purpose The aim of this study was to evaluate the diagnostic accuracy of the 1 mg dexamethasone suppression test (DST) for the prediction of autonomous cortisol secretion (ACS)-related comorbidities in patients with adrenal incidentalomas (AIs). Methods This was a retrospective multicenter study. We recruited patients with AI/s >= 1 cm, excluding those who, during the study, were found during the extension study of an extra-adrenal cancer, with a known diagnosis of hereditary syndromes characterized by adrenal tumors, those presenting with overt hormonal excess syndromes, and those in whom the DST results were missing. Results A total of 823 patients met the inclusion criteria. Based on the 1.8, 3.0, and 5.0 mu g/dl post-DST cortisol thresholds, the prevalence of ACS was 33.5%, 13.7%, and 5.6%, respectively. The prevalence of hypertension (OR = 1.8, 95% CI = 1.3-2.4), diabetes (OR = 1.6, 95% CI = 1.2-2.2), and dyslipidemia (OR = 1.4, 95% CI = 1.0-1.9) was higher with cortisol post-DST >= 1.8 mu g/dl; the prevalence of hypertension (OR = 2.1, 95% CI = 1.4-3.3) and diabetes (OR = 1.7, 95% CI = 1.1-2.6) was higher with values >= 3.0 mu g/dl; and the prevalence of hypertension (OR = 2.0, 95% CI = 1.0-3.7) was higher with levels >= 5.0 mu g/dl. However, the diagnostic accuracy of the DST for the prediction of cardiometabolic comorbidities in patients with AIs was poor, with areas under the ROC curve < 0.61. Conclusions The DST is a poor predictor of cardiometabolic comorbidities in patients with AIs regardless of the cortisol cut-off values applied. This finding suggests that the diagnosis of ACS should not be based solely on the results of the DST. Other clinical, metabolic, or imaging markers showing a better performance for the prediction of the development and progression of cardiometabolic comorbidities in AIs need to be identified.

Automated summary

This study aimed to evaluate the diagnostic accuracy of the 1 mg dexamethasone suppression test for predicting ACS-related comorbidities in patients with AIs. The DST showed poor performance in predicting cardiometabolic comorbidities in AIs patients, regardless of cortisol cut-off values.