NOVEL APPROACHES TO EVALUATE BONE QUALITY IN PARATHYROID GLAND DISEASES

Abstract project 1 Context: Primary hyperparathyroidism (PHPT) is associated with impaired bone quality and increased fracture risk. Reliable tools for the evaluation of bone quality parameters are not yet clinically available. Bone Strain Index (BSI) is a new metric for bone strength based on Finite Element Analysis from lumbar spine and femoral neck dual-energy x-ray absorptiometry (DXA) images. Objective: To assess the lumbar spine (LS), femoral neck (FN), and total hip (TH) BSI in PHPT patients compared with controls and to investigate the association of BSI with vertebral fractures (VFs) in PHPT. Methods: This case-control study enrolled 50 PHPT patients and 100 age- and sexmatched control subjects from an outpatient clinic. The main outcome measures were LS-BSI, FN-BSI, and TH-BSI. Results: FN bone mineral density (BMD) and one-third distal radius BMD were lower in the PHPT group than in controls (FN 0.633 ± 0.112 vs 0.666± 0.081, P = 0.042; radius 0.566 ± 0.07 vs 0.625 ± 0.06, P < 0.001). PHPT group has significant lower TBS score compared with controls (1.24 ± 0.09 vs 1.30 ± 0.10, P < 0.001). BSI was significantly higher at LS (2.28 ± 0.59 vs 2.02 ± 0.43, P = 0.009), FN (1.72 ± 0.41 vs 1.49 ± 0.35, P = 0.001), and TH (1.51 ± 0.33 vs 1.36 ± 0.25, P = 0.002) in PHPT. LS-BSI showed moderate accuracy for discriminating VFs (AUC 0.667; 95% CI, 0.513-0.820). LS-BSI ≥ 2.2 and was a statistically significant independent predictor of VFs, with an adjusted odds ratio ranging from 5.7 to 15.1. Conclusion: BSI, a DXA-derived bone quality index, is impaired in PHPT and may help to identify PHPT subjects at high risk of fractures Abstract project 2 Introduction The natural history and bone involvement of normocalcemic hyperparathyroidism (NHPT) are not fully clarified yet. The bone strain index (BSI) is a deformation index based on the finite element method and can be applied to DXA scans. In this study, we aim to assess BSI in subjects with NHPT. Method A case–control study included 170 subjects: 40 subjects with NHPT, 50 subjects with primary hypercalcemichyperparathyroidism (PHPT), and 80 controls (age- and sex-matched with the NPTH group). Results Lumbar spine (LS) bone mineral density (BMD), femoral neck (FN) BMD, total hip (TH) BMD, and TBS weresimilar between NHPT and both PHPT and controls. FN-BSI was lower in NHPT compared to PHPT (1.52 ± 0.31 vs1.72 ± 0.42 p = 0.031) while there were no differences between NHPT and controls. TH-BSI was lower in NHPT comparedto PHPT (1.36 ± 0.23 vs 1.52 ± 0.34, p = 0.030), while there were no differences between NHPT and controls. LS-BSI was not different between NHPT and both PHPT and controls. Conclusion The trabecular and cortical bones assessed by BSI seem not to be significantly impaired in NHPT. Furtherprospective studies are needed to confirm these findings and to give an insight into the natural history of NHPT to improve knowledge and management of this condition Abstract project 3 Methods: This case-control study enrolled 50 PHPT patients and 100 age- and sexmatched control subjects from an outpatient clinic. The main outcome measures were LS-BSI, FN-BSI, and TH-BSI. Results: FN bone mineral density (BMD) and one-third distal radius BMD were lower in the PHPT group than in controls (FN 0.633 ± 0.112 vs 0.666 ± 0.081, P = 0.042; radius 0.566 ± 0.07 vs 0.625 ± 0.06, P < 0.001). PHPT group has significant lower TBS score compared with controls (1.24 ± 0.09 vs 1.30 ± 0.10, P < 0.001). BSI was significantly higher at LS (2.28 ± 0.59 vs 2.02 ± 0.43, P = 0.009), FN (1.72 ± 0.41 vs 1.49 ± 0.35, P = 0.001), and TH (1.51 ± 0.33 vs 1.36 ± 0.25, P = 0.002) in PHPT. LS-BSI showed moderate accuracy for discriminating VFs (AUC 0.667; 95% CI, 0.513-0.820). LS-BSI ≥ 2.2 and was a statistically significant independent predictor of VFs, with an adjusted odds ratio ranging from 5.7 to 15.1. Conclusion: BSI, a DXA-derived bone quality index, is impaired in PHPT and may help to identify PHPT subjects at high risk of fractures