Trabecular bone score (TBS) in Cushing's disease: TBS gain after hypercortisolism normalization

Abstract

ContextHypercortisolism frequently induces trabecular bone loss, more pronounced at the lumbar spine, resulting in osteoporosis, and thus an increase in fracture risk. Several studies have shown bone mass recovery in patients with Cushing's disease (CD) after treatment. ObjectiveTo examine treatment effects on TBS (trabecular bone score) in addition to aBMD (areal bone mineral density) in a cohort of patients with CD. Design and settingSingle-center retrospective longitudinal study in patients diagnosed with CD and successfully treated following surgery and/or medical treatment. PatientsWe included 31 patients with median age and BMI (body mass index) of 37.7 [28.4;43.3] years old and 27.7 [25.8;30.4] kg/m2, respectively. Median 24 h urinary cortisol before treatment was 213.4 [168.5;478.5] μg/24 h. All subjects were completely biochemically controlled or cured after treatment. Main outcome measuresaBMD and TBS were evaluated at AP Spine (L1-L4) with DXA prodigy (GE-Lunar), QDR 4500 (Hologic), and TBS iNsight® (Med-Imaps) before and after treatment. ResultsAbsolute TBS and aBMD gains following cure of CD were significant (p < 0.0001, and p < 0.001, respectively). aBMD and TBS increased by +3.9 and 8.2 % respectively after cure of CD. aBMD and TBS were not correlated before (p = 0.43) and after treatment (p = 0.53). Linear regression analyses showed that TBS gain was independent of baseline BMI and that low TBS at baseline was predictive of TBS gain after treatment. ConclusionThe more significant improvement of microarchitecture assessed by TBS than aBMD and the absence of correlation between TBS and aBMD suggest that TBS may be an adequate marker of bone restoration after cure of CD. To support this conclusion, future studies with larger sample sizes and longer follow-up periods should be carried out.