Changes of computed tomography-based body composition after adrenalectomy in patients with endogenous hypercortisolism.

Abstract

Data on longitudinal changes of computed tomography (CT)-determined visceral fat area (VFA), skeletal muscle area (SMA) and skeletal muscle radiodensity (SMD) after adrenalectomy are limited in patients with hypercortisolism. To examine the association of severity of cortisol excess and improvement of CT-based muscle and fat parameters after adrenalectomy. Retrospective observational cohort study. One hundred thirty-four patients with overt Cushing's syndrome (CS; n=39), mild autonomous cortisol excess (MACE; n=57), or nonfunctioning adrenal tumour (NFAT; n=38) at a tertiary endocrinology institution between 2006 and 2017 were included. Changes in CT-determined VFA, visceral-to-subcutaneous fat ratio (VSR), SMA, skeletal muscle index (SMI), and SMD measured at the third lumbar vertebra (L3). At baseline, CS patients had higher VFA, lower SMA, SMI and SMD values, compared to NFAT or MACE patients. Compared to NFAT, significant decreases in VFA and increases in SMA, SMI and SMD was observed in CS 1year after adrenalectomy. In MACE, adjusted mean changes of SMD but not VFA, SMA or SMI differ significantly compared to NFAT (+8.9% vs -3.4%, P=0.032). In a multivariate linear regression model, the increase by 1μg/dL of post-dexamethasone serum cortisol at baseline was independently associated with greater reduction of VFA (-3.95%), VSR (-3.07%), and increase in SMD (+0.92%, P<0.05 for all) after adrenalectomy. The severity of cortisol excess was associated with greater improvement of L3 VFA, VSR and SMD 1year after adrenalectomy. These CT-based markers may allow more objective assessment of treatment benefit at earlier stage.