Oral Presentation ESA-SRB-APEG-NZSE 2022

Cardiovascular risk markers in adults with adrenal adenoma and possible autonomous cortisol secretion (#228)

Angela Xun-Nan Chen 1 2 , Anjana Radhakutty 2 3 , Sophie Drake 1 , Andrew Kiu 4 , Cambpell Thompson 5 , Morton Burt 1 2
  1. Endocrinology, Flinders Medical Centre, Bedford Park, SA, Australia
  2. School of Medicine, Flinders University, Bedford Park, SA, Australia
  3. Medicine, Lyell McEwin Hospital, Elizabeth Vale, SA, Australia
  4. Breast and Endocrine Surgery, Flinders Medical Centre, Bedford Park, SA, Australia
  5. General Medicine, Royal Adelaide Hospital, Adelaide , South Australia, Australia

Adrenal adenomas are identified in 5% of abdominal computer tomography. While surgical treatment of overt hypercortisolaemia is recommended, many adenomas have possible autonomous cortisol secretion (PACS), defined as morning cortisol 50–138 nmol/L after 1 mg dexamethasone suppression test (DST). While PACS is associated with increased cardiovascular mortality, it is not clear whether cortisol secretion underlies this association. We investigated mechanisms that may link PACS and cardiovascular mortality in adults with adrenal adenoma.

In this cross-sectional study, we characterised 18 adults with adrenal adenoma and PACS (64±11 years, 6 males) and 18 controls with non-functioning adrenal adenoma (66±10 years, 8 males). Reactive hyperaemia index (RHI) was measured by peripheral artery tonometry to quantify endothelial function and 24-hour ambulatory blood pressure (24h AMBP) monitoring was performed. Indices of insulin secretion and sensitivity were estimated by measuring glucose and insulin fasting and 30-minutely for two hours following a mixed meal (10 kcal/kg, 45% carbohydrate, 15% protein, 40% fat). Whole body composition was assessed by dual-energy x-ray absorptiometry.

Participants with PACS had significantly higher cortisol after 1 mg DST and 24-hour urinary free cortisol (24h UFC) and lower dehydroepiandrosterone sulphate than controls. Fasting glucose and glucose area under the curve after the mixed meal were higher and insulin secretion index trended lower in participants with PACS. There were no significant differences in Matusda Index, RHI, 24h AMBP or total or central fat mass between the groups (Table). Cortisol after 1 mg DST was weakly, but positively, associated with fasting glucose (r2=0.12, p=0.04).   

Adults with adrenal adenoma and PACS demonstrated fasting and postprandial hyperglycaemia with a trend towards lower insulin secretion, but no difference in insulin sensitivity, endothelial function, hypertension or fat mass. Hyperglycaemia secondary to impaired insulin secretion not sensitivity may underlie the association between PACS and increased cardiovascular mortality.

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