Association of Hormonal Activity with CT-Derived Body Composition Characteristics in Patients with Adrenal Adenomas

Background/Objectives: To compare computed tomography (CT)-derived body composition parameters across hormonal subtypes of adrenal adenomas and investigate their associations with hormonal activity. Methods: This retrospective study included 171 patients with unilateral adrenal adenomas categorized as Cushing syndrome (CS), mild autonomous cortisol secretion (MACS), non-functioning adenoma (NFA), or primary aldosteronism (PA). Adipose tissue and skeletal muscle parameters were quantified on CT images at the third lumbar vertebral (L3) level. Comparisons were adjusted for age, sex, and body mass index, and associations between hormonal and body composition parameters were assessed. Results: After adjustment, significant differences in non-psoas skeletal muscle index (SMI) were observed among the groups. Non-psoas SMI was lower in the CS group than in all other groups and in the MACS group than in the NFA and PA groups. Muscle attenuation was significantly reduced only in the CS group. In multivariable analyses adjusted for age, sex, and BMI, higher post-dexamethasone cortisol levels were independently associated with lower skeletal muscle parameters, with the strongest association observed for non-psoas SMI (β = −0.396, p < 0.001). Adipose tissue parameters did not differ significantly among hormonal subtypes. In exploratory analyses, aldosterone levels and the aldosterone-to-renin ratio were positively associated with the visceral-to-subcutaneous fat area ratio. Conclusions: Cortisol excess in adrenal adenomas was associated primarily with alterations in skeletal muscle mass and quality, particularly within the non-psoas compartment. Adipose tissue parameters demonstrated more heterogeneous associations with hormonal activity. These findings support further investigation of CT-derived body composition parameters across hormonal subtypes of adrenal adenomas.