Clinical indices and anthropometric measures for magnetic resonance imaging-defined visceral adiposity across the hypercortisolism spectrum.

OBJECTIVE

Conventional anthropometric measures may inadequately capture metabolically relevant fat redistribution in hypercortisolism. We evaluated the discriminative performance of clinical indices (Hepatic Steatosis Index [HSI], Visceral Adiposity Index [VAI], Metabolic Score for Visceral Fat [METS-VF]) and anthropometric measures (body mass index [BMI], waist circumference) for MRI-defined visceral adiposity across the hypercortisolism spectrum.

DESIGN AND

METHODS

In this cross-sectional study, 65 participants were included: 13 with active Cushing's disease (CD), 12 with CD in remission, 30 with mild autonomous cortisol secretion (MACS), and 10 healthy controls. Abdominal MRI with proton density fat fraction separately quantified visceral (VAT), hepatic, and pancreatic fat. Index performance for visceral adiposity (VAT >130 cm²) was assessed among participants with hypercortisolism (n=55).

RESULTS

VAT differed across groups (p=0.02), highest in MACS (230.8 [164.9-292.4] cm²). VAT was associated with HOMA-IR (r=0.5, p=0.009) and HbA1c (r=0.4, p=0.001) but not with circulating cortisol. Hepatic and pancreatic fat did not differ across groups; hepatic fat correlated with HOMA-IR and pancreatic fat with HbA1c, but neither with cortisol. HSI was the only index reaching significance for visceral adiposity (AUC 0.82, 95% CI: 0.68-0.96, p=0.002), at a cohort-derived cut-off of 39.25 (sensitivity 87%, positive predictive value 93%); METS-VF, BMI, and waist circumference did not (all p≥0.1). Among participants without obesity (BMI <30 kg/m², n=31), HSI classification remained associated with visceral adiposity (p=0.001).

CONCLUSION

In endogenous hypercortisolism, ectopic fat distribution was more closely associated with metabolic burden rather than cortisol levels. HSI may have potential as an exploratory screening adjunct for occult visceral adiposity, particularly in patients without obesity, pending external validation.