Increased Risk of Vertebral Fractures in Patients With Mild Autonomous Cortisol Secretion

The risk of vertebral fractures (VFx) in patients with adrenal incidentalomas (AI) and mild autonomous cortisol secretion (MACS) is debated.

To evaluate the VFx prevalence and incidence in patients with AI and MACS.

This cross-sectional and longitudinal study using retrospective data from 4 Italian endocrinology units included 444 patients (cross-sectional arm) and 126 patients (longitudinal arm, 24.9 ± 5.3 months follow-up) to evaluate prevalent and incident VFx, respectively, in patients with MACS (MACS-yes) and without MACS (MACS-no). The main outcome measures were serum cortisol after a 1-mg dexamethasone test (F-1mgDST), bone mineral density (BMD) by dual-energy x-ray absorptiometry at spine (LS) and femur (FN), and VFx presence by x-ray.

Cross-sectional arm: 214 and 230 patients were MACS-yes and MACS-no, respectively, based on F-1mgDST >1.8 µg/dL (50 nmol/L). Patients with MACS had higher VFx prevalence (62.6%) than those without MACS (22.9%, P < .001); MACS was associated with prevalent VFx (odds ratio, 5.203; 95% CI, 3.361-8.055; P < .001; relative risk [RR] 2.07), regardless of age, body mass index, gender distribution, LS-BMD, and presence of type 2 diabetes mellitus (T2D). Longitudinal arm: 66 and 60 patients were MACS-no and MACS-yes, respectively. Patients without MACS showed higher number of incident VFx (36.4%) than patients without MACS (10.0%, P < .001); MACS was associated with the presence of an incident VFx (RR 4.561; 95% CI, 1.600-13.003; P = .005) regardless of age, LS-BMD, gender distribution, presence of prevalent VFx, and T2D. Results were confirmed in women and men when separately evaluated.

Women and men with AI and MACS are at higher risk of VFx.