Are nonfunctioning adrenal incidentalomas really nonfunctioning? A retrospective single-center study

In patients with adrenal incidentaloma (AI), cortisol levels <1.8 μg/dL after a dexamethasone suppression test (DST) are considered nonfunctioning in terms of autonomic cortisol hypersecretion (ACH). We aimed to investigate the frequency of hypertension (HT) in patients with nonfunctioning AI.

Individuals with AI who were admitted to the endocrinology clinic between September 2020 and May 2023 were included as the patient group, and age- and gender-matched individuals admitted with thyroid nodules between the same dates were included as the control group.

The participants included 123 AI patients who fulfilled the study criteria and 114 age- and sex-matched patients with thyroid nodules (age: 53.0±10.9 years and 52.9±7.4 years, respectively, p=0.98; female/male distribution: 90/33 and 91/23, respectively, p=0.28). The frequency of HT was higher in the AI group than in the control group (50.4% and 31.6%, respectively, p=0.004). The frequency of HT was significantly lower in patients with a DST result <0.87 μg/dL compared to those with a DST result ≥0.87 μg/dL (42.6% and 66.1%, respectively, p=0.009). The factors affecting HT were analyzed using binary logistic regression analysis; it was found that age [β=0.068, odds ratio (OR); 1.07 (95% confidence interval (CI); 1.02-1.12), p=0.004] and DST [β=1.18, OR; 3.24 (95% CI); 1.02-10.34, p=0.047] were independent factors.

The frequency of HT increases in patients with nonfunctioning AI. The reason for this increase may possibly be the presence of ACH, which is not detected by the cut-off values we currently use to exclude ACH.