Yasir Elhassan, Fares Alahdab, Alessandro Prete, et al. Natural history of adrenal incidentalomas with and without mild autonomous cortisol excess. Ann Intern Med. 2019;171(2):107-116.
Incidental detection of adrenal masses has increased due to the use of cross-sectional imaging. These adrenal incidentalomas are found in approximately 5% of patients, with increasing incidence by age. Most adrenal incidentalomas are benign, nonfunctioning adrenal tumors (NFATs), but up to 15% are associated with excess hormone secretion. These secretory adenomas are often associated with autonomous cortisol secretion, a condition characterized by elevated levels of cortisol without the typical physical changes associated with hypercortisolism.* A better understanding of the natural history of these two adenoma types is required to determine appropriate management and follow-up plans for both NFATs and autonomous cortisol secretion.
To determine the natural history of adrenal incidentalomas, a systematic review and meta-analysis analyzed 32 studies reporting the outcomes of 4,121 patients with NFAT or autonomous cortisol secretion.† Specific outcomes of interest included adenoma growth, changes in hormone production, the frequency of cardiovascular and metabolic comorbidities‡ between baseline and follow-up, and all-cause and cardiovascular mortality.
The meta-analysis showed that patients with autonomous cortisol secretion had a higher prevalence of cardiovascular risk factors at baseline and were more likely to develop or show worsening of these factors during follow-up than patients with NFAT. Additionally, patients with NFATs were at elevated risk for type 2 diabetes and cardiovascular comorbidities relative to patients without any adrenal adenomas. Although adenoma growth and changes in hormonal function were relatively stable over time, the meta-analysis concluded that clinical follow-up is required for patients with NFAT or autonomous cortisol secretion due to their increased risk for cardiometabolic comorbidities.*This summary uses the term autonomous cortisol secretion to conform with the nomenclature used by the American Association of Clinical Endocrinologists (AACE). According to the AACE, an incidentally discovered adrenal mass with a 1-mg post-dexamethasone suppression test (DST) >1.8 μg/dL may indicate autonomous cortisol secretion. For more information, see Vaidya A, Hamrahian A, Bancos I, Fleseriu M, Ghayee HK. The evaluation of incidentally discovered adrenal masses. Endocr Pract. 2019;25(2):178-192.†Definition criteria for autonomous cortisol secretion varied across studies and included DST cortisol cutoff thresholds ranging from 1.8 to 5 μg/dL.‡Cardiovascular and metabolic comorbidities included hypertension, obesity or weight gain, dyslipidemia, type 2 diabetes, and cardiovascular events.
Comorbid Condition(s) at Baseline
Comorbidities were more likely to develop and worsen in patients with autonomous cortisol secretion than in those with NFAT.
Compared with the NFAT group, patients with autonomous cortisol secretion were more than twice as likely to gain weight (21% vs 8.7%, respectively).
Newly Developing or Worsening Comorbid Condition(s) at Follow-Up*Data on worsening of obesity/weight gain were not included in the meta-analysis.
Patients with autonomous cortisol secretion were twice as likely to experience a new cardiovascular event (15.5% of 222 patients vs 6.4% of 613 patients, respectively) than patients with NFATs.
Patients Experiencing a New Cardiovascular Event
Because of the increased risk of cardiovascular comorbidities with adrenal adenomas—independent of cortisol secretion patterns—clinical follow-up should be performed to assess and manage these comorbidities.