Mild autonomous cortisol secretion in adrenal incidentalomas and risk of fragility fractures: a large cross-sectional study

Objective: Mild autonomous cortisol secretion (MACS) has been associated with a higher prevalence of osteoporosis, although most data rely on single-center studies with limited sample size. We aimed to assess the prevalence of fragility fractures and contributing factors in a large cohort of patients with adrenal incidentalomas. Design and methods: Medical records of 1023 patients with adrenal incidentalomas from 1990 to 2019 were reviewed, and 735 patients were selected. Clinically obtained electronic radiological images closest to first endocrine evaluation, such as lateral views of spine X-rays or CT thoraco-abdominal scans, were reviewed to screen for asymptomatic morphometric vertebral fractures. Clinical fragility fractures, hormonal, and dual-energy x-ray absorptiometry (DXA) indices were also recorded. Results: Four hundred seventy-four patients had nonfunctioning (NF) adrenal incidentalomas, 238 had MACS and 23 adrenal Cushing's syndrome (AC). Prevalence of fragility fractures was different (P = .018) between groups, respectively, 24.1% (NF), 34.0% (MACS), and 30.4% (AC), with significant difference between NF and MACS (P = .012). When analyzed separately by sex and menopausal status, this difference remained significant in postmenopausal women (P = .011), with a fracture prevalence of 22.2% (NF) and 34.6% (MACS). Fracture prevalence was similar in males. Women with MACS aged ≥65 years reported a 48.8% prevalence of fractures, as compared with 29.5% in NF (P < .01). In postmenopausal women, fragility fractures were associated with age (odds ratio [OR] 1.1, P < .001), smoking (OR 1.8, P = .048), and 1 mg-dexamethasone suppression test (DST) cortisol (OR 3.1, P = .029), while in men, only age was associated with fragility fractures. Conclusions: A considerable fracture burden was shown in postmenopausal women with adrenal incidentalomas and MACS, with clinical implications for the evaluation and management of bone metabolism.