Is trabecular bone score (TBS) a useful tool in primary hyperparathyroidism?

Posted September 23, 2021

A study conducted by the INCT Hormona team at the Federal University of São Paulo (UNIFESP) aimed to evaluate the usefulness of trabecular bone score (TBS) measurements combined with dual X-ray absorptiometry (DXA) values. The purpose was to provide a more accurate assessment of the risk of bone fragility in patients with primary hyperparathyroidism (PHPT).

The study titled “Trabecular Bone Score (TBS) in Primary Hyperparathyroidism (PHPT):A Useful Tool?” had been granted an award during the V Workshop on Integration of Basic and Clinical Sciences in Osteometabolism, held on October 26, 2019, in São Paulo, Brazil, organized by the Brazilian Association for Bone Evaluation and Osteometabolism (ABRASSO). The full-text article is available at

According to the Institute’s coordinator at UNIFESP, Dr. Marise Lazaretti Castro, TBS is a software-based method that can be used on densitometry devices and complements their results by assessing the structure of the trabecular bone. “PHPT may often lead to bone loss, even in its asymptomatic presentations,” she says.

Methods and results

The article is part of the doctoral thesis written by Livia Marcela dos Santos and advised by Dr. Marise. According to the research advisor, 64 patients diagnosed with primary hyperparathyroidism between 2017 and 2019 participated in the study before surgery, in addition to 63 controls.

TBS and bone mineral density (BMD) estimated by DXA at the lumbar spine, total hip, femoral neck, and distal third radius were determined in patients and controls. “Vertebral fractures were analyzed by VFA [vertebral fracture assessment] on the DXA device itself and classified according to the Genant method,” she explains.

“As expected, patients with PHPT had lower BMD values than controls at all sites assessed. TBS measurements were also statistically lower in patients with PHPT than controls (mean PHPT TBS = 1.233 vs. control TBS = 1.280; p = 0.044),” explains Dr. Marise. “Osteoporosis was found in 50% of patients with PHPT and 26.6% of controls (p = 0.02). However, a lumbar spine T-score <-2.5 was found only in 21.8% of patients with PHPT,” she explains.

In the study, vertebral fractures were detected in nine patients (14%) in the PHPT group and four patients (6.3%) in the control group (p = 0.24). Also, TBS measurements were more discriminatory to assess the risk of vertebral fractures than conventional DXA.

“The ROC curve showed that TBS values <1.187 are associated with a significantly higher risk of vertebral fracture in patients with PHPT (p = 0.02),” the doctor says.

Finally, the study concluded that TBS used as a complement to DXA measurement is a useful tool to assess bone fragility more accurately in patients with PHPT.