What FRAX (Fracture Risk Assessment) score indicates the need for osteoporosis treatment?

FRAX Score Thresholds for Osteoporosis Treatment

Treatment is indicated when the FRAX 10-year probability of major osteoporotic fracture is ≥20% or hip fracture is ≥3%, regardless of age. 1

FRAX Thresholds by Guidelines

FRAX (Fracture Risk Assessment Tool) is designed to calculate the 10-year probability of fracture based on clinical risk factors with or without bone mineral density (BMD) measurements. According to the most recent guidelines, treatment thresholds are clearly defined:

Primary Treatment Thresholds:

• Major osteoporotic fracture risk ≥20% (age-independent) 1
• Hip fracture risk ≥3% (age-independent) 1

Additional Risk Stratification:

Different organizations categorize fracture risk slightly differently:

• Very high fracture risk: 1

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

• High fracture risk: 1

  • BMD T-score ≤−2.5 but >−3.5
  • FRAX 10-year risk of major osteoporotic fracture ≥20% but <30% or hip fracture ≥3% but <4.5%

• Moderate fracture risk: 1

  • FRAX 10-year risk of major osteoporotic fracture ≥10% and <20%
  • Hip fracture risk >1% and <3%
  • BMD T-score between −1 and −2.4

Clinical Application of FRAX

FRAX can be calculated with or without BMD measurements, though including BMD generally improves predictive accuracy 1. The tool has demonstrated strong predictive ability for both major osteoporotic fractures and hip fractures across different populations 2.

Important considerations:

1. BMD inclusion improves accuracy: FRAX with BMD shows better predictive performance than FRAX without BMD 3

2. Age effects: Older age may affect concordance between FRAX with and without BMD 3

3. Chronic conditions: FRAX maintains good predictive value even in patients with chronic kidney disease 4

4. Treatment monitoring: FRAX is not responsive enough to be used as a target for goal-directed treatment, as scores typically increase slowly over time even with treatment 5

Special Populations

• Glucocorticoid users: For patients on glucocorticoids >7.5 mg/day, multiply the 10-year risk of major osteoporotic fracture by 1.15 and hip fracture risk by 1.2 1

• Adults under 40: FRAX is not validated for this age group; different risk assessment approaches are needed 1

Common Pitfalls

1. Overreliance on BMD alone: While BMD provides the definition of osteoporosis, it is only one of many risk factors for fracture. FRAX incorporates multiple clinical risk factors for more comprehensive assessment.

2. Threshold variability: FRAX intervention thresholds may vary between countries 1, so using country-specific guidelines is important.

3. Not adjusting for glucocorticoid use: Failing to apply the appropriate adjustment for patients on glucocorticoids can lead to underestimation of fracture risk.

4. Using FRAX for treatment monitoring: FRAX is not designed or responsive enough to monitor treatment effects 5.

By using these evidence-based FRAX thresholds of ≥20% for major osteoporotic fracture or ≥3% for hip fracture, clinicians can identify patients who would benefit from pharmacological intervention to reduce fracture risk.