Endocrine Abstracts

Objective: To study the differences in the metabolic profile of patients with non-functioning adrenal adenomas (NFA) and autonomous cortisol secretion (ACS).

Methods: 143 patients diagnosed of adrenal incidentaloma (AI) between 2010 and 2018 were retrospectively analyzed. AI was defined as an adrenal mass≥1 cm, accidentally discovered by radiologic examination. ACS was confirmed by serum cortisol post-dexamethasone suppression test (Nugent)≥3 μg/dl and no typical features of Cushing’s Syndrome (CS). NFA were considered when the whole hormonal evaluation was normal (Nugent test<3 μg/dl, aldosterone/renin ratio (when appropriate) and urinary metanephrines). The statistical analysis was performed with STATA 15.0 and ACS and NFA patients were included (n=132).

Results: The mean age was 63.2(10.74) years and 55.9% were women. 78.3% patients had NFA, 11.9% ACS, 1.4% CS and 8.4% other diagnoses. In the univariate analysis, we found no statistically significant differences between ACS and NFA in the prevalence of hypertension (70.6 vs 47.8%, P=0.08), diabetes (35.3 vs 26.1%, P=0.4), dyslipidemia (47.1 vs 48.7%, P=0.9), cardiovascular (17.7 vs 8.8%, P=0.3) and cerebrovascular disease (11.8 vs 3.5%, P=0.1). The prevalence of obesity was significantly lower in ACS than in NFA (17.7 vs 37.7%, P=0.01), however no statistically significant differences were found in the BMI (28.0 vs 30.0 kg/m², P=0.4). Neither significant differences were found in the mean of systolic or diastolic blood pressure (128.4 vs 131.5 mmHg (P=0.48) and 76.6 vs 78.8 mmHg, (P=0.47), respectively); fasting plasma glucose (FPG) (109.4 vs 107.8 mg/dl, P=0.83), total cholesterol (188.5 vs 188.2 mg/dl, P=0.98); LDL (108.5 vs 115.1 mg/dl, P=0.52), HDL (52.5 vs 53.1 mg/dl, P=0.93) and triglycerides (133.2 vs 125.9 mg/dl, P=0.68). No significant correlation was found between Nugent test and cardiovascular risk factors (p>0.05 in the Pearson correlation). In the linear regression model, Nugent test was a good predictor of the maximum adenoma diameter (R-squared=0.13, P=0.01) and urinary free cortisol (R-squared=0.23, P=0.00) but it was inadequate to predict ACTH, basal cortisol, DHEAS, FPG, cholesterol, LDL, HDL or triglycerides (P>0.05). There was no progression to CS in any case and only 3 NFA developed ACS during the study period (mean=27.7 months). In both groups, the metabolic profile remained stable throughout the follow-up.

Conclusions: Our data suggest a higher prevalence of hypertension, diabetes mellitus, cardiovascular and cerebrovascular disease in patients with ACS compared to NFA. However, there were no statistically significantly differences probably due to small sample size. We did not find the Nugent test to be a reliable predictor of the metabolic profile in AI patients.