Abstract
OBJECTIVE: This study aimed to compare body composition measurements between patients with nonfunctional adrenal incidentalomas (NFAI) and mild autonomous cortisol secretion (MACS) using bioelectrical impedance analysis (BIA) and anthropometric methods. SUBJECTS AND METHODS: This cross-sectional study included patients diagnosed with MACS or NFAI. Body composition was assessed using BIA, anthropometric measurements, and the Durnin and Womersley (DW) method. Correlation and Bland-Altman analyses were performed to assess the relationship and agreement between the DW method and BIA. RESULTS: Fifty-seven patients (32 with MACS and 25 with NFAI) were included; those with MACS were older (p = 0.004). Post-dexamethasone suppression test cortisol levels (p < 0.001) and the incidence of bilateral tumors (p = 0.017) were higher in MACS patients. No significant differences in body composition parameters were observed between the MACS and NFAI groups. A strong correlation was observed between BIA- and DW-derived fat mass in MACS patients (r = 0.890, p < 0.001). Bland-Altman analysis revealed a slight mean bias for body fat mass of -0.4 kg (limits of agreement: -9.14-8.34 kg) and for body fat percentage of -0.83% (limits of agreement: -11.32-9.66%) between methods. CONCLUSION: A robust correlation and acceptable agreement was demonstrated between the DW method and BIA for estimating body fat. The DW equation may provide a practical and low-cost alternative for assessing body composition in MACS and NFAI cohorts. Limitations include the lack of a healthy control group and the inability to validate BIA and anthropometric estimates against gold-standard imaging techniques, potentially introducing accuracy bias.