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

FRAX Score Thresholds for Osteoporosis Treatment

Treatment for osteoporosis should be initiated when the FRAX score indicates a 10-year risk of major osteoporotic fracture ≥20% or a 10-year risk of hip fracture ≥3%. 1

Risk Stratification Using FRAX

FRAX (Fracture Risk Assessment Tool) is a validated instrument that calculates the 10-year probability of experiencing a major osteoporotic fracture or hip fracture. According to current guidelines, fracture risk categories are defined as:

• High fracture risk:

  • FRAX 10-year risk of major osteoporotic fracture ≥20%
  • FRAX 10-year risk of hip fracture ≥3%
  • Prior osteoporotic fracture(s)
  • Hip or spine bone mineral density T-score ≤-2.5 in men age ≥50 years and postmenopausal women 2, 1

• Moderate fracture risk:

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

• Low fracture risk:

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

Treatment Recommendations Based on Risk Category

Treatment decisions should be guided by the patient's fracture risk category:

• High risk patients: Pharmacologic therapy is recommended

  • First-line: Oral bisphosphonates (alendronate or risedronate)
  • For very high risk (FRAX >30% for major osteoporotic fracture or >4.5% for hip fracture): Consider anabolic agents 2, 1

• Moderate risk patients: Consider pharmacologic therapy based on individual factors and patient preferences

• Low risk patients: Non-pharmacologic measures (calcium, vitamin D, exercise)

Important Clinical Considerations

1. T-scores should be included when calculating FRAX scores whenever available. Research shows that FRAX scores generated without T-scores may lead to inappropriate treatment recommendations - potentially recommending treatment for patients with normal BMD while not recommending treatment for patients with osteoporosis 3.

2. Most patients with high FRAX scores have osteoporosis by BMD criteria. Studies show that 85% of individuals designated as high risk for major osteoporotic fracture by FRAX have a T-score in the osteoporotic range at one or more measurement sites 4.

3. Special populations require adjustments to FRAX calculations:

   • For patients on glucocorticoids >7.5 mg/day, increase the FRAX-generated risk by 1.15 for major osteoporotic fracture and 1.2 for hip fracture 2
   • For patients with very recent fractures, imminent fracture risk may be higher than calculated by FRAX 2

4. Absolute benefit of treatment is greatest in high-risk patients. While relative risk reduction with treatments like alendronate is similar across FRAX scores, the absolute benefit is greatest among those with highest fracture probabilities 5.

Practical Application

When evaluating patients for osteoporosis treatment:

1. Calculate FRAX score with femoral neck BMD when available
2. Determine risk category based on thresholds (high: ≥20% major osteoporotic or ≥3% hip fracture)
3. Consider other clinical factors that might modify risk (recent fracture, glucocorticoid use)
4. Initiate appropriate treatment based on risk category

This approach aligns with current guidelines that recommend using FRAX to guide treatment decisions rather than relying solely on BMD T-scores.