What is the clinical significance of a Frax (Fracture Risk Assessment Tool) score in osteoporosis management?

Clinical Significance of FRAX Score in Osteoporosis Management

The FRAX (Fracture Risk Assessment Tool) score is a highly valuable clinical tool that calculates 10-year probability of major osteoporotic fractures and hip fractures, providing essential guidance for treatment decisions in osteoporosis management beyond BMD measurements alone. 1

What is FRAX?

• FRAX is a computer-based algorithm developed by the Sheffield WHO Collaborating Centre for Metabolic Bone Diseases, first released in 2008, designed for use in primary care settings 1
• It calculates the 10-year probability of major fractures (hip, clinical spine, humerus, or wrist) and hip fracture specifically in men and women 1
• FRAX incorporates easily obtainable clinical risk factors including age, BMI, prior fragility fracture, parental hip fracture history, smoking status, glucocorticoid use, rheumatoid arthritis, secondary osteoporosis, and alcohol consumption 1, 2
• Femoral neck BMD can be optionally included to enhance fracture risk prediction 1

Why FRAX is Clinically Significant

• BMD alone has limitations - it is specific but not sensitive for fracture risk, meaning most fractures occur in people with BMD above the osteoporosis threshold (T-score > -2.5) 1
• FRAX captures risk factors that are independent of BMD and may be reversible with anti-osteoporosis treatment 1
• It provides an individualized absolute fracture risk assessment that can guide treatment decisions 2, 3
• FRAX helps identify patients with osteopenia (T-score between -1.0 and -2.5) who would benefit from pharmacologic intervention despite not meeting the BMD threshold for osteoporosis 2, 4

Treatment Thresholds Based on FRAX

• According to National Osteoporosis Foundation guidelines, treatment is recommended for patients with:
  • 10-year risk of hip fracture ≥3% or
  • 10-year risk of major osteoporotic fracture ≥20% 2, 3
• These thresholds help clinicians determine which patients with low bone mass (but not osteoporosis by BMD criteria) should receive pharmacologic therapy 2, 3
• European guidance sets the intervention threshold at the age-specific probability of future fracture conveyed by the presence of a prior fragility fracture 1

Clinical Applications of FRAX

• Helps determine which patients should undergo DXA scanning 5
• Guides treatment decisions in patients with osteopenia 2, 3
• Particularly valuable for assessing fracture risk in patients on glucocorticoid therapy 2
• Can be used to identify high-risk patients who may benefit from more aggressive treatment approaches 6, 4
• Assists in determining not just whether to treat, but what agents to use based on risk stratification 6

Limitations and Considerations

• FRAX does not account for dose-dependent effects of risk factors like glucocorticoids and alcohol 2
• The tool has limitations regarding race-specific calculations 2
• FRAX is validated for adults aged 40-90 years; it should not be used for younger patients 2
• While FRAX can be used in patients currently or previously treated for osteoporosis, it should not be used to assess treatment-related fracture risk reduction 7
• FRAX accuracy improves when BMD is included in the calculation 2, 4

Integration into Clinical Practice

• FRAX should be used alongside clinical fracture risk assessment, including evaluation of falls, fractures, and frailty 2
• For postmenopausal women and men over 50 with low bone mass but not osteoporosis, FRAX helps identify those needing treatment 2, 4
• In patients on glucocorticoids, FRAX should be adjusted by increasing major osteoporotic fracture risk by 1.15 and hip fracture risk by 1.2 if prednisone dose >7.5 mg/day 2
• Reassessment intervals of 1-3 years are recommended for adults on continued glucocorticoid treatment who are not on osteoporosis medication 2

Clinical Impact on Patient Outcomes

• Using FRAX to guide treatment decisions can help reduce morbidity and mortality associated with osteoporotic fractures 4
• Proper use of FRAX can help avoid unnecessary DXA scans in low-risk patients, improving healthcare resource utilization 5
• By identifying high-risk patients who might not meet traditional BMD criteria for treatment, FRAX helps prevent fractures that would otherwise occur 3, 4
• FRAX enables more equitable targeting of treatment to those at increased risk of fracture 6