What Is the FRAX Tool?
Developed by the World Health Organization (WHO), the FRAX tool is a free, web-based tool used globally to estimate a patient's 10-year risk of a major osteoporotic or hip fracture. It provides a more comprehensive assessment by integrating various clinical risk factors instead of relying solely on bone mineral density (BMD) test results. FRAX helps identify patients with low bone mass (osteopenia) who are at high risk for fracture and guides clinicians in determining who might benefit from further evaluation or treatment. The tool is widely available online and incorporated into clinical guidelines.
How Does FRAX Calculate Your Risk?
The FRAX tool calculates fracture risk using country-specific algorithms based on several input factors. These include patient demographics like age, sex, weight, and height, a history of prior fragility fracture, parental history of hip fracture, lifestyle factors such as smoking and alcohol consumption, medical conditions like rheumatoid arthritis, and long-term oral use of glucocorticoids. Including femoral neck DEXA results is optional but recommended to refine the calculation.
Interpreting Your FRAX Results
FRAX provides the 10-year probability of a major osteoporotic fracture and the 10-year probability of a hip fracture. These scores are used with national guidelines to inform treatment decisions. For instance, in the US, specific thresholds for hip fracture (3% or higher) or major osteoporotic fracture (20% or higher) probability may indicate the need for pharmacological treatment. Lower scores might suggest that lifestyle changes and monitoring are sufficient.
How Healthcare Providers Use FRAX for Treatment Decisions
FRAX assists healthcare providers in discussing bone health with patients by:
- Risk Stratification: Identifying high-risk individuals with osteopenia who may benefit from treatment.
- Targeted Intervention: Guiding therapeutic choices based on absolute fracture risk.
- Shared Decision-Making: Providing a quantitative risk estimate for informed patient decisions.
- Cost-Effectiveness: Helping to prioritize pharmacological intervention for those most likely to benefit.
Limitations of the FRAX Tool
FRAX has limitations that require clinical consideration:
- Binary Inputs: Uses simple 'yes/no' for factors like prior fractures or glucocorticoid use, not accounting for severity or dose.
- Exclusion of Falls: Does not include fall history, a significant fracture risk factor.
- BMD Site Limitations: Only uses femoral neck BMD, which may not capture risk accurately in all cases.
- Untreated Patients Only: Intended for patients not currently on osteoporosis treatment.
Comparison of BMD and FRAX Assessment
| Feature | Bone Mineral Density (BMD) Test | FRAX Tool |
|---|---|---|
| Focus | Measures bone density at a specific site | Estimates 10-year fracture probability using multiple factors |
| Output | A T-score and Z-score | Percentage probabilities for major osteoporotic and hip fractures |
| Factors | Only measures bone density; doesn't incorporate clinical risk factors directly | Integrates BMD (optional) with clinical risk factors like age, sex, and lifestyle |
| Application | Diagnosing osteoporosis or osteopenia | Predicting fracture risk and guiding treatment for those with low bone mass |
| Limitations | Low sensitivity, as many fractures occur in people with osteopenia | Simplistic inputs for some factors; doesn't account for falls |
The Evolution of Fracture Risk Assessment
Ongoing research aims to improve fracture risk assessment. A developing version, FRAXplus, is intended to include more detailed information, such as dose-response relationships for glucocorticoids and a history of falls, for more accurate risk prediction.
Conclusion
FRAX provides a valuable and validated method for assessing an individual's 10-year fracture risk by combining clinical factors with or without BMD data. While not without limitations, it has significantly advanced the management of patients at risk for osteoporosis-related fractures, supporting crucial decisions to prevent serious injuries. The tool is an important aid for informed decision-making. More information and access to the tool can be found on {Link: FRAX website https://frax.shef.ac.uk/FRAX/}.
