At what fracture risk assessment (FRAX) score should treatment for osteoporosis be initiated?

When to Start Treatment for Osteoporosis Based on FRAX

Treatment for osteoporosis should be initiated when the FRAX 10-year risk of major osteoporotic fracture is ≥20% or hip fracture risk is ≥3%, or in patients with prior osteoporotic fractures regardless of FRAX score. 1

Fracture Risk Categories and Treatment Thresholds

The decision to initiate osteoporosis treatment should be based on absolute fracture risk assessment using the FRAX tool, which incorporates clinical risk factors with or without BMD measurements.

Adults ≥40 Years of Age:

• High Fracture Risk (requires treatment):

  • Prior osteoporotic fracture(s)
  • BMD T-score ≤-2.5
  • FRAX 10-year risk of major osteoporotic fracture ≥20%
  • FRAX 10-year risk of hip fracture ≥3% 2, 1

• Very High Fracture Risk (requires treatment, preferably with anabolic agents):

  • Prior osteoporotic fracture(s)
  • BMD T-score ≤-3.5
  • FRAX 10-year risk of major osteoporotic fracture ≥30%
  • FRAX 10-year risk of hip fracture ≥4.5% 2, 1

• Moderate Fracture Risk (consider treatment):

  • FRAX 10-year risk of major osteoporotic fracture 10-19%
  • FRAX 10-year risk of hip fracture >1% and <3% 2

• Low Fracture Risk (generally no pharmacologic treatment):

  • FRAX 10-year risk of major osteoporotic fracture <10%
  • FRAX 10-year risk of hip fracture ≤1% 2

Special Considerations for Glucocorticoid Users:

For patients on glucocorticoids, the fracture risk is higher, and FRAX adjustments are needed:

• For doses >7.5 mg/day, multiply the 10-year risk of major osteoporotic fracture by 1.15 and hip fracture by 1.2 2
• Example: If hip fracture risk is 2.0%, adjusted risk would be 2.4% 2

Clinical Implementation of FRAX for Treatment Decisions

1. Calculate FRAX score using country-specific tools (available at https://www.shef.ac.uk/FRAX/tool.jsp)
2. Adjust FRAX score if patient is on glucocorticoids >7.5 mg/day
3. Determine risk category based on FRAX results and presence of prior fractures
4. Initiate treatment if patient meets high-risk criteria

Important Clinical Considerations:

• BMD measurement is valuable but not always necessary for treatment decisions. Studies show 83.8% concordance between FRAX calculations with and without BMD 3.

• Discordance between FRAX with and without BMD is more common in elderly patients, those with lower BMD, and those with FRAX scores near intervention thresholds 3.

• Most patients designated as high risk by FRAX (with femoral neck BMD) have T-scores in the osteoporotic range at one or more measurement sites (83-85% for major osteoporotic fracture risk; 64-66% for hip fracture risk) 4.

• Very few high-risk patients (<1%) have normal T-scores at all measurement sites 4.

Common Pitfalls and Caveats

1. FRAX is validated only for untreated patients aged 40-90 years 5. Do not use FRAX to assess fracture risk in patients already on osteoporosis treatment.

2. FRAX does not account for dose-response relationships for several risk factors (e.g., alcohol, smoking, glucocorticoids) beyond binary yes/no inputs 6.

3. FRAX does not include falls history, which is an important independent risk factor. Use clinical judgment to adjust treatment decisions in patients with frequent falls 5.

4. FRAX may underestimate fracture risk in patients with:

   • Multiple prior fractures (FRAX only accounts for presence/absence of fracture)
   • Recent fractures (higher imminent risk)
   • Very low BMD (T-score < -3.5)
   • High-dose or long-term glucocorticoid use 2

5. Country-specific FRAX tools should be used whenever possible, as fracture rates vary significantly between countries 7.

By using FRAX to guide treatment decisions, clinicians can direct osteoporosis therapies to those at highest risk of fracture, improving outcomes related to morbidity, mortality, and quality of life.