Cortisol as a Marker for Increased Mortality in Patients with Incidental Adrenocortical Adenomas

Context: Incidental benign adrenocortical adenomas, adrenal incidentalomas are found in 4.5% of abdominal computed tomography scans, with the incidence increasing to 10% in patients older than 70 years of age. These incidentalomas frequently show evidence of excess cortisol secretion but without overt Cushing's syndrome. The mortality rate is increased in Cushing's syndrome. Objective: This study sought to investigate whether patients with adrenal incidentalomas have an increased mortality. Design: This was a retrospective, longitudinal cohort study. Setting: The study was carried out in an Endocrine Investigation Unit in a University Teaching Hospital. Patients: Two hundred seventy-two consecutive patients with an incidental adrenal mass underwent a dedicated diagnostic protocol, which included dexamethasone testing for hypercortisolism between 2005 and 2013. Overall survival was assessed in 206 patients with a benign, adrenocortical adenoma. Main Outcome Measures: Survival analysis was carried out by using Kaplan-Meier curves and the effect of dexamethasone cortisol estimated by Cox-regression analysis. Cause-specific mortality was ascertained from death certificates and compared with local and national data. Results: Eighteen of 206 patients died and the mean time (SD) from diagnosis to death was 3.2 (1.7) years. Seventeen of 18 patients who died had a post dexamethasone cortisol > 1.8 mu g/dL and there was a significant decrease in survival rate with increasing dexamethasone cortisol levels (P = .001). Compared with the < 1.8 mu g/dL group, the hazard ratio (95% confidence interval) for the 1.8-5 mu g/dL group was 12.0 (1.6-92.6) whereas that of the > 5 mu g/dL group was 22.0 (2.6-188.3). Fifty percent and 33% of deaths were secondary to circulatory or respiratory/infective causes, respectively. Conclusions: Patients with adrenal incidentalomas and a post-dexamethasone serum cortisol > 1.8 mu g/dL have increased mortality, mainly related to cardiovascular disease and infection.