Resetting the Abnormal Circadian Cortisol Rhythm in Adrenal Incidentaloma Patients With Mild Autonomous Cortisol Secretion.

Context: Adrenal incidentalomas (AIs) are found commonly on axial imaging. Around 30% exhibit autonomous cortisol secretion (ACS) associated with increased cardiovascular events and death. Objective: We hypothesized that AI/ACS patients have an abnormal cortisol rhythm that could be reversed by use of carefully timed short-acting cortisol synthesis blockade, with improvement in cardiovascular disease markers. Design, Setting, and Participants: In a phase 1/2a, prospective study (Eudract no. 2012-002586-35), we recruited six patients with AI/ACS and two control groups of six sex-, age-, and body mass index-matched individuals: (1) patients with AI and no ACS (AI/NoACS) and (2) healthy volunteers with no AI [healthy controls (HC)]. Twenty-four-hour circadian cortisol analysis was performed to determine any differences between groups and timing of intervention for cortisol lowering using the 11ß-hydroxylase inhibitor metyrapone. Circadian profiles of serum interleukin-6 (IL-6) were assessed. Results: Serum cortisol levels in group AI/ACS were significantly higher than both group AI/NoACS and group HC from 6 pm to 10 pm [area under the curve (AUC) difference: 0.81 nmol/L/h; P = 0.01] and from 10 pm to 2 am (AUC difference: 0.86 nmol/L/h; P < 0.001). In light of these findings, patients with ACS received metyrapone 500 mg at 6 pm and 250 mg at 10 pm, and cortisol rhythms were reassessed. Postintervention evening serum cortisol was lowered, similar to controls [6 pm to 10 pm (AUC difference: -0.06 nmol/L/h; P = 0.85); 10 pm to 2 am (AUC difference: 0.10 nmol/L/h; P = 0.76)]. Salivary cortisone showed analogous changes. IL-6 levels were elevated before treatment [10 pm to 2 pm (AUC difference: 0.42 pg/mL/h; P = 0.01)] and normalized post treatment. Conclusions: In AI/ACS, the evening and nocturnal cortisol exposure is increased. Use of timed evening doses of metyrapone resets the cortisol rhythm to normal. This unique treatment paradigm is associated with a reduction in the cardiovascular risk marker IL-6.