Endocrine Abstracts

Background and aim: The relationship between sarcopenia and overt cortisol excess as in Cushing’s syndrome is well-known. However, only a few studies investigated the relationship between autonomous cortisol secretion (ACS) in adrenal incidentalomas and skeletal muscle mass. The aims of our study were to analyze the skeletal muscle mass in patients with adrenal incidentalomas and to investigate the correlations with hormonal data.

Methods: We enrolled 200 adult patients (>18 years) without clinical signs of Cushing syndrome, bearing monolateral and bilateral benign adrenal incidentaloma detected at CT scan. We classified the adrenal tumors as non-secreting (NS) or ACS according to cortisol levels after 1-mg dexamethasone suppression test (DST) < or >50 nmol/l, respectively. Skeletal muscle mass was evaluated by Skeletal Muscle index (SMI) through a threshold segmentation (-19HU – +150HU) of the Skeletal Muscle Area on an L3 slice of the basal acquisition, subsequently divided by the height squared. Subjects underwent measurement of an 11-steroid profile in serum by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS).

Results: SMI was lower in ACS than NS subjects (40.6±1.2 vs 44.2±1.2; P=0.007). Accordingly, the prevalence of sarcopenia was higher in ACS than NS patients (59.4% vs 39.6%; P=0.012). Similar results were confirmed after analyzing the data separately by sex. Overall, we identified correlations between SMI and age (r=-0.34; P<0.001), body mass index (BMI) (r=0.39; P<0.001), basal cortisol (r=-0.155; P=0.041) and post-DST cortisol (r=-0.180; P=0.018). When analyzed separately by sex, similar correlations were confirmed in males, whereas only the correlations between SMI and basal cortisol, age, and BMI were observed in post-menopausal women. Additionally, in post-menopausal women, SMI was associated positively with DHEAs levels (r=0.318; P=0.004) and negatively with corticosterone (r=-0.259; P=0.007). Multivariable analysis by generalized linear model (GLM) showed a positive correlation between SMI and BMI (B=0,009; 95% C.I. 0.005 - 0.013; P<0.001), independently of age (P=0.205) and post-DST cortisol (P=0.078) in males. In post-menopausal females, GLM highlighted an independent correlation between SMI and DHEAs levels (B=0.036; 95% C.I. 0.005-0.068; P=0.024), with an independent contribution of BMI (B=0.004; 95% C.I. 0.002-0.007; P=0.001) and age (B=-0.002; 95% C.I. -0.004-0.000; P=0.017).

Conclusions: ACS is associated with impaired skeletal muscle mass, despite patients may not report symptoms of sarcopenia. A differential hormonal contribution to impaired skeletal muscle mass has been identified according to sex.