Assessment of vertebral microarchitecture in overt and mild Cushing's syndrome using trabecular bone score

ObjectiveOsteoporotic fractures associated with Cushing's syndrome (CS) may occur despite normal bone mineral density (BMD). Few studies have described alterations in vertebral microarchitecture in glucocorticoid-treated patients and during CS. Trabecular bone score (TBS) estimates trabecular microarchitecture from dual-energy X-ray absorptiometry acquisitions. Our aim was to compare vertebral BMD and TBS in patients with overt CS and mild autonomous cortisol secretion (MACE), and following cure of overt CS. SettingUniversity Hospital. DesignMonocentric retrospective cross-sectional and longitudinal studies of consecutive patients. PatientsA total of 110 patients were studied: 53 patients had CS (35, 11 and 7 patients with Cushing's disease, bilateral macronodular adrenal hyperplasia and ectopic ACTH secretion respectively); 39 patients had MACE (10 patients with a late post-operative recurrence of Cushing's disease and 29 patients with adrenal incidentalomas); 18 patients with non-secreting adrenal incidentalomas. 14 patients with overt CS were followed for up to 2years after cure. ResultsVertebral osteoporosis at BMD and degraded microarchitecture at TBS were found in 24% and 43% of patients with CS, respectively (P<.03). As compared to patients with nonsecreting incidentalomas, patients with MACE had significantly decreased TBS (P<.04) but not BMD. Overt fragility fractures tended to be associated with low TBS (P=.07) but not with low BMD. TBS, but not BMD values, decreased with the intensity of hypercortisolism independently of its aetiology (P<.01). Following remission of CS, TBS improved more markedly and rapidly than BMD (10% vs 3%, respectively; P<.02). ConclusionTrabecular bone score may be a promising, noninvasive, widely available and inexpensive complementary tool for the routine assessment of the impact of CS and MACE on bone in clinical practice.