Clinical Application of FRAX ™ adjusted for TBS

Sheffield FRAX™ Group has opted for a convenient way to incorporate TBS into the existing workflow: integrate it into the FRAX™ risk assessment as an adjustment parameter.

  • How was the model developed?
    • FRAX™ group has defined a model of clinical application of TBS, as an adjustment parameter of FRAX 10-year probabilities of fracture (both hip and Major Osteoporotic Fractures (MOF));
    • FRAX™ Adjusted for TBS will account for FRAX™, TBS, age and death hazard;
    • The model was built based on the retrospective analysis of the prospective cohort of Manitoba, Canada, analyzing 33 352 women and men aged 40 to 99, with a mean follow-up of 4.7 years.1
    • The model was then cross-validated in an individual level population-based meta-analysis – gathering more than 17 800 women and men from 14 countries.2
  • How does it work concretely?
    • In terms of clinical practice, there will be no change in clinicians’ workflow:
      • You will fill in the standard FRAX™ questionnaire with BMD results;
      • When you validate the data and get your patients FRAX™ results, you will see a new “ Adjust with TBS” button appearing underneath the FRAX™ results table;
      • Press the “Adjust with TBS” button;
      • Enter your patients’ TBS score to get the FRAX™ Adjusted for TBS 10-year fracture risk probabilities: TBS values calculated with TBS iNsight™ version 2.1 and above can be used;
      • You now have both Adjusted-FRAX™ 10-year probabilities for hip and MOF fractures that you can use for risk assessment.
  • What should I use it for?
    • FRAX™ Adjusted for TBS allows:
      • Refinement of individual fracture risk assessment
      • Reclassification of patients’ risk for future fracture near the intervention threshold.
  • What clinical consequences may be observed?
    • Potential shift from one side to the other of the cut-off value for treatment indication: you may observe a shift from non-therapy to therapy group and vice-versa;
    • Higher impact of TBS in the adjusted FRAX™ in the assessment of MOF fracture than of Hip Fracture;
    • Stronger contributing effect of TBS in younger adults;
    • Stronger contributing effect of TBS in patients whose standard FRAX™ scores are around borders of intervention thresholds.

Illustration of TBS contributing effect in the context of patients whose standard FRAX™ scores are around borders of intervention thresholds.

FRAX

 This illustration of FRAX™ Adjusted for TBS is based on the National Osteoporosis Guideline Group (NOGG) age-dependent intervention threshold.

The NOGG was established to provide a clinical guideline for FRAX™ integration into patient management; NOGG members are Prof JE Compston (Chair), Dr AL Cooper, Prof C Cooper, Prof R Francis, Prof D Marsh, Prof EV McCloskey, Prof JA Kanis, Prof D Reid, Dr P Selby, Mrs C Bowring and Mr C Davies. Visit the NOGG page on Sheffield website for further information: http://www.shef.ac.uk/NOGG/index.html

Comment: In this specific zone, one would observe the most significant individual clinical benefit in terms of risk re-categorization as they would potentially shift from one side of the intervention threshold to the other as a function of TBS value. Indeed, based on FRAX™ Adjusted for TBS and on the corresponding risk evaluation, the patient eligibility for treatment will be reclassified.

  • Patients initially situated in the “blue zone” would either shift from non-therapy to therapy group, based on a low TBS or get a decreased risk based on a high TBS value.
  • Patient initially situated in the “red zone” would either shift from therapy to non-therapy group, based on their high TBS or get a worsened risk based on a low TBS.

On the overall population, FRAX™ Adjusted for TBS will increase fracture predictability accuracy and help fine tune individual risk assessment.


References

2Adjust fracture probability by Trabecular Bone Score, E.V. McCloskey et al., CTI 2015

3 A meta-analysis of trabecular bone score in fracture risk prediction and its interaction with FRAX, J. A. Kanis, Oral presentation, WCO-IOF-ESCEO 2015, Milan