Endocrine Abstracts

Background: Autonomous cortisol secretion (ACS) in patients with adrenal incidentalomas (AI) has been associated with increased mortality in previous small studies. Our aim was to evaluate if ACS is a risk factor for mortality in a large population of patients with AI.

Methods: Consecutive patients examined for adrenal adenomas, found as AI, without catecholamine or aldosterone hypersecretion between 2005 and 2015 were included and followed for up to 14 years (Clinicaltrials.gov, NCT03919734). Patients were grouped according to predefined levels of cortisol after 1-mg dexamethasone suppression test (DST) (< 50, 50–83, 84–138 and >138 nmol/l). Controls matched for sex and age were randomly selected from the general population (3:1 ratio). Mortality data were collected from the National Registry. Mortality rates were adjusted for age, sex and cardiovascular risk factors.

Results: 3980 individuals were included, 995 patients and 2985 controls, of which 170 and 429 died (mean follow-up-time 6.9 years). Mortality rates were similar between controls and patients with DST < 50 (n = 561) and DST50-83 (n = 267), hazard ratio (HR) 0.98 (0.73–1.30) and HR 0.96 (0.70–1.32). Compared to DST < 50, mortality was similar in the DST50–83 group, HR 1.26 (0.86–1.85).

DST84-138 (n = 105) and DST > 138 (n = 62) had increased mortality both compared to controls, HR 1.80 (1.19–2.74) and HR 4.06 (2.31–7.15) respectively, and to DST < 50, HR 2.13 (1.38–3.29) and HR 2.91 (1.73–4.89) respectively.

Conclusion: In patients with an AI, a cortisol after DST > 83 nmol/l seems to be a clinically significant risk factor for mortality, while a lower value indicates a risk comparable to the general population.