Risk guide

Fracture risk: how FRAX-style bone scores work

Fracture risk tools estimate the probability of a major osteoporotic fracture — hip, spine, forearm or shoulder — over the next ten years, using clinical risk factors that you can answer without a scan.

What it needs

  • Age, sex, weight and height
  • Previous fragility fracture
  • Parental hip fracture
  • Current smoking and alcohol intake of three or more units daily
  • Glucocorticoid use, including current dose
  • Rheumatoid arthritis and secondary osteoporosis
  • Femoral neck bone mineral density, when available

How to read the result

You get two numbers: the 10-year probability of a major osteoporotic fracture and of a hip fracture specifically. Treatment thresholds vary by country, but a major fracture probability of 20% or a hip probability of 3% is a common trigger for intervention.

Bone density is optional but powerful

The model works without a DXA result, which is why it is useful as a first pass. Adding femoral neck bone mineral density usually narrows the estimate considerably and can move you across a treatment threshold in either direction.

Where it falls short

Clinical risk factors are treated as yes or no, so a very high steroid dose and a very low one count similarly unless dose adjustment is applied. Falls risk, which drives many real fractures, is not part of the calculation.

Source

Kanis JA et al., FRAX methodology, Osteoporosis International

This guide is educational. It is not a diagnosis and does not replace a conversation with a qualified clinician.

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