Trabecular bone score and bone mineral density as indices of skeletal fragility in endogenous Cushing's syndrome

Abstract

Objective: Endogenous Cushing's syndrome (CS) is a known cause of secondary osteoporosis. Vertebral fractures (VFs) in endogenous CS may occur despite normal bone mineral density (BMD). Trabecular bone score (TBS) is a relatively new, noninvasive technique to assess bone microarchitecture. The objective of our study was to analyse the BMD and bone microarchitecture using TBS in endogenous CS and compare it with a group of age and sex-matched healthy controls, and also analyse the factors predicting BMD and TBS.Design: Cross-sectional study of cases and controls.Patients and measurements: We included 40 female patients with overt endogenous CS, out of which 32 were adrenocorticotropic hormone (ACTH)dependent CS and 8 were ACTH-independent. We also included 40 healthy, female controls. Both patients and controls were subjected to an assessment of biochemical parameters and BMD and TBS.Results: Patients with endogenous CS had significantly lower BMD at the lumbar spine, femoral neck, and total hip and significantly lower TBS than healthy controls (all p < .001), while no significant difference was noted in the distal radius BMD (p = .055). In endogenous CS, a large proportion of patients, n = 13 (32.5%) had normal BMD for age (BMD Z-score ≥ −2.0) with low TBS (L 1 -L 4 TBS ≤ 1.34). TBS correlated negatively with HbA1c (p = .006), and positively with serum T4 (p = .027). Conclusion: TBS should be considered an important complementary tool in additionto BMD for the routine assessment of skeletal health in CS. K E Y W O R D S bone microarchitecture, bone mineral density, cortisol, Cushing's syndrome, trabecular bone score 1 | INTRODUCTION Endogenous Cushing's syndrome (CS) is a relatively rare endocrine disease with an incidence of 3.2 cases per million population per year. 1 Previous studies have shown that both exogenous and endogenous glucocorticoid excess leads to an increased risk of fragility fractures. 2 The underlying mechanisms include excess cortisol mediating negative calcium balance with decreased calcium re-absorption from the gut and impaired conversion of 25-hydroxyvitamin D [25(OH)D] to its active form, calcitriol. Excess cortisol also

The Severity of Bone Loss in Cushing’s Diseases

“…Rahaman et al [18] found a negative correlation with morning serum cortisol and BMD at LS (r 2 = 0.09, P = 0.08) and hip (r 2 = 0.09, P = 0.09), although this is not statistically significant. Likewise, Boro et al [1] reported that BMD at the L1-L4 level showed significant negative correlations with plasma cortisol at 8 a.m. (Spearman's rho ρ = -.397, p =.011).…”

“…Similarly, femoral neck BMD also had significant positive correlations with weight and BMI (femoral neck BMD; ρ =.590, p <.001 for weight and ρ =.503, p <. 001 for BMI) [1].…”

“…Another study conducted by Boro et al found a significantly lower BMD at the lumbar level (Z-score at -2.2 [IQR -2.7 to -0.7]) than at the femoral neck (Z-score at -1.7 [IQR -2.4 to -0.6]) in patients with endogenous Cushing's syndrome [1].…”

“…Excess in cortisol results in a shift of mesenchymal stem cells toward adipogenesis rather than osteoblastogenesis, an increased RANK-L expression with increased osteoclastic bone resorption, and an osteoblast autophagy [1].…”

Acromegaly and Bone: An Update

“…Novel tools for assessing bone quality and resistance have recently emerged as having added value for predicting fractures in various forms of osteoporosis [ 42 , 43 ]. So far, some of these tools have also been tested as fracture predictors in osteopathies driven by pituitary hyperfunction [ 44 ] and specifically in acromegaly, since they could possibly overcome the abovementioned limitations of areal DXA evaluation in patients affected by this disease [ 45 ]. Briefly, bone quality in acromegaly has been assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT), a three-dimensional noninvasive imaging technique that scans the extremities and can assess volumetric bone density and microarchitecture of cortical and cancellous bone [ 46 ].…”