Endocrine Abstracts

Objectives: Mean TBS (Trabecular Bone Score) values are generally lower in PHPT (primary hyperparathyroidism) patients than controls. The aim of this study was to assess TBS from spine DXA images in patients with PHPT and look at its correlates.

Methods: This was a cross-sectional study conducted in an osteoporosis referral center. One hundred and thirty six patients with PHPT were selected from our database (2010–2016) if they had a valid LS DXA scan. The patients were both females (20% premenopausal) and males (12%), mean age 59.4 yrs (range 16–83), with both asymptomatic and symptomatic PHPT (mean PTH 226 pg/ml, mean serum calcium 11.3 mg/dl); a third of the patients were severely vitamin D deficient (<10 ng/ml). TBS indices were derived from LS-DXA images and cutoff points used in term of fracture risk were those previously reported.

Results: Mean TBS values of the group was 1.26±0.12. TBS Z-score was negatively and significantly correlated with serum PTH, serum Calcium, Osteocalcin (r=−0.275, P=0.005) and mostly C-telopeptide (r=−0.314, P=0.001). Actually TBS values and both T and Z scores correlated negatively and significantly with serum C-telopeptide. TBS was in the partially degraded range but did not differ by vitamin D status, even when compared with severely deficient patients (35 pts, mean TBS 1.25). PTH correlated negatively with 25OHD and TBS correlated strongly (r=0.536) with aBMD.

Conclusion: We observed a good and negative correlation between TBS and serum C-telopeptide which favor the notion that TBS might reflect degraded microarchitecture.