Usefulness Of Trabecular Bone Score(TBS) To Identify Bone Quality And Bone Fragility In Patients With Primary Hyperparathyroidism And Hypercortisolism

Objective: Patients with primary hyperparathyroidism(PHPT)and hypercortisolism(Cushing’s syndrome)are prone to decline in bone strength,so patients have increased osteoporosis and even fractures,the conventional Dual-energy X-ray absorptiometry(DXA)can not evaluate the bone condition of these patients accurately.Trabecular bone score(TBS)is a new method to evaluate bone microstructure indirectly,which describes bone quality by grey-level texture measurements on lumbar spine dual X-ray absorptiometry(DXA)images.The purpose of this retrospective study was to investigate the usefulness of trabecular bone score in bone quality and bone fragility in patients with primary hyperparathyroidism and hypercortisolism.Methods: The clinical data of 82 cases of primary hyperparathyroidism and 50 cases of hypercortisolism was collected from the Department of endocrinology of Tianjin Medical University General Hospital.Bone mineral density(BMD)and trabecular bone score(TBS)were measured by DXA and TBS i Nsight software.Then we analyzed the relationship between trabecular bone score and bone quality and bone fragility in patients with primary hyperparathyroidism and hypercortisolism and calculated FRAX index with and without the adjustment of TBS,respectively.Results:(1)Of the 82 patients with hyperparathyroidism,62% showed degraded bone microstructure,39% were diagnosed as osteoporosis by DXA,and the fracture rate was 15.8%;of the 50 patients with hypercortisolism,70% showed degraded bone microstructure,22% was diagnosed as osteoporosis,and fracture rate was 14%.(2)Trabecular bone score was negatively correlated with alkaline phosphatase levels(P =0.000,r =-0.369)and moderately positively correlated with lumbar spine BMD(P =0.000,r = 0.587),femoral neck BMD(P = 0.000,r = 0.497),total hip Bone mineral density(P = 0.000,r = 0.506).However,there was no significant relationship between trabecular with age or BMI.(3)The lumbar BMD,femoral neck,and total hip bone mineral density in the PHPT group were lower than those in the hypercortisolism group(P<0.05),and the three bone turnover markers(OC、CTX、PINP)were higher than those in the hypercortisolism group(P<0.05),but TBS was not statisticallysignificant.(4There were statistical differences in alkaline phosphatase,osteocalcin,BMD,and FRAX between normal TBS group,partially degraded TBS group and severely degraded TBS group(P <0.05);however,there was no significant difference in fracture rates among the three groups(P> 0.05).(5)All 132 patients were divided into fracture group and non-fracture group.The levels of CTX and FRAX index between the two groups were statistically different(P <0.05),and there were no significant differences in bone density and TBS.Among the PHPT group,the BMD of the fracture group was lower than that of the non-fracture group and the FRAX index was higher than that of the non-fracture group(P <0.05).There was no statistical difference in TBS between the fracture group and non-fracture group.Among the hypercortisolism patients,there were no statistical difference in the bone mineral density and TBS between the fracture group and the non-fracture group;however,PMOF was statistically different between the two groups(P <0.05).(6)TBS is a predictor of osteoporosis in PHPT patients(P = 0.001,OR = 0.122,95% CI[0.037-0.398]),even after adjusting for age,gender,BMI(P = 0.001,OR = 0.120,95% CI [0.033-0.435]);Conversely,TBS was not a predictor of osteoporosis in patients with hypercortisolism no matter whether adjusting confounding factors or not.(7)The sensitivity of FRAX in the prediction of fracture risk among patients with PHPT and hypercortisolism is higher than TBS alone.The sensitivity of combined TBS and FRAX is not significantly different from the RFAX alone.Conclusions: Trabecular bone score and BMD are different in evaluating bone quality.TBS combined with bone mineral density(BMD)can increase the diagnostic accuracy of this type of secondary osteoporosis such as primary hyperparathyroidism and hypercortisolism.Moreover,in patients with PHPT and hypercortisolism,FRAX is more sensitive to fracture prediction than TBS.