Abstract
IntroductionThe impairment in bone microarchitecture and reduced bone quality are relevant mechanisms underlying the increased fracture risk in Cushing’s syndrome (CS). The trabecular bone score (TBS) is a relatively novel textural index of bone microarchitecture.PurposeThe objective of the study was to compare TBS, bone mineral density (BMD), and fracture risk in patients with endogenous CS to controls. We have investigated the association of TBS with anthropometric parameters and 25(OH) vitamin D concentrations.Materials and MethodsThe study group comprised 19 consecutive patients with CS (14 women and 5 men; mean age 45.84 ± 13.15 years) and sex-, age-matched 36 controls (25 women and men; mean age 52.47 ± 8.98 years). Anthropometric parameters, biochemical and hormonal data were compared between groups. Lumbar spine (L1–L4) and femoral neck BMD (LS BMD, FN BMD) measurements were performed. TBS values were obtained from lumbar spine DXA images.ResultsTBS was significantly lower in patients with CS compared to controls (p = 0.0002). The 10-year probability of hip fracture and the 10-year probability of a major osteoporotic fracture were significantly higher in the CS group than in controls (p = 0.03, p < 0.0001, respectively). All subjects from the CS group with fractures had low TBS value (degraded microarchitecture). TBS correlated negatively with the duration of disease in patients with CS (r = -0.590 p = 0.008).ConclusionsThe patients with active CS have altered bone microstructure as indicated by the decreased TBS and are at higher risk of hip and a major osteoporotic fractures. TBS seems to be a very important analytical tool facilitating fracture risk assessment in endogenous hypercortisolism.
Highlights
The impairment in bone microarchitecture and reduced bone quality are relevant mechanisms underlying the increased fracture risk in Cushing’s syndrome (CS)
The following data were collected: results of basal and dynamic evaluation of the hypothalamic– pituitary–adrenal (HPA) axis, including adrenocorticotropic hormone (ACTH) concentrations, urinary free cortisol (UFC), cortisol circadian rhythm, morning serum cortisol levels after the overnight 1 mg dexamethasone suppression test (1 mg DST) and suppression tests with 2 mg and 8 mg dexamethasone, 25(OH) vitamin D, dehydroepiandrosterone sulfate (DHEA-S), estradiol (E2), total testosterone, calcium, and alkaline phosphatase (ALP)
There were no significant differences in age, sex, height, weight, and body mass index (BMI) between studied groups
Summary
The impairment in bone microarchitecture and reduced bone quality are relevant mechanisms underlying the increased fracture risk in Cushing’s syndrome (CS). Patients with endogenous CS have an increased risk of fragility fractures, despite normal or slightly decreased bone mineral density (BMD). This could be explained by decreased bone strength due to the qualitative deterioration of bone structure [10,11,12]. The trabecular bone score (TBS) is a relatively novel textural index of bone microarchitecture derived from lumbar spine DXA images. It appears to be a parameter capable of providing indirect information on trabecular bone microarchitecture and bone quality [16, 17]. A large meta-analysis confirmed that TBS is a significant predictor of fracture risk independently of FRAX probability [20]
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