INTERPRETATION OF TBS & BMD VALUES

Interpreting TBS values and Bone Density

Use in Patient Management

TBS – Trabecular Bone Score - is an aid for patient management. All diagnosis and treatment
decisions require clinical judgment and consideration of the clinical context of the patient.Risk
stratification of TBS and BMD could improve the assessment of fracture risk, particularly in
osteopenic patients and patients with secondary osteoporosis. The following interpretation table1
presents the level of risk expressed as the number of major osteoporotic fractures per 1000
women/year (based on a study conducted on 30,000 women). It shows that for a given BMD
category the risk may almost double depending on TBS.

TBS is a risk factor for future low trauma fracture independent of BMD and clinical risk factors.
TBS should be interpreted in accordance with the recommendations of national & international
societies, e.g. NOF2 , ESCEO3 , ISCD4 and GRIO5 .

Clinical Case

Osteopenic BMD T-score and low TBS

Patient clinical background

A 63-year-old woman referred for bone density testing with the following background: mother with
forearm history fracture, no previous fracture, regular calcium and vitamin D intake, hysterectomy at
41-year-old (no oophorectomy).

Bone assessment and analysis images:

• BMD:
  • Osteopenic spine BMD (L1-L4): T-sore = -1.4
    • Normal femur BMD:
    • Femoral neck T-score = -1.5
    • Total hip BMD T-score=-1.3
• TBS:
  • Degraded bone texture: TBS (L1-L4) =1.073
• FRAX
  • MOF (%) = 4.7
  • HF (%) = 0.8
• FRAX Adjusted for TBS:
  • MOF (%) = 7.5-HF (%) = 1.52

  • CAROC Assessment: Low risk of fracture

Conclusion and patient management decision:

Based on clinical risk of fracture for the patient our recommendation was to assure and adequate
calcium intake as well as Vitamin D and training exercise for bone strength.

Referral physician decided to start anti-resorptive treatment (Risedronate 5mg daily).

Endnotes

1. Adapted from Hans et al. JBMR 2011; 26(11): 2762-9 and meta-analysis from McCloskey et al. JBMR. 2016, 31(5): 940-948.
2. NOF Clinician’s Guidelines to prevention and Treatment of Osteoporosis 2010 – Last update in april 2014.
3. Harvey et al. Bone, 2015. (78): 216–224.
4. ISCD http://www.iscd.org/official-positions/ - Last update in june 2015 with TBS integration
5. GRIO http://www.grio.org/ Research and Information Group on Osteoporosis