What is a fracture risk assessment tool?
A fracture risk assessment tool (FRAT), most notably the World Health Organization's FRAX®, is an online calculator used by healthcare providers to estimate a person's 10-year probability of an osteoporotic fracture. It uses clinical risk factors (CRFs) and, optionally, bone mineral density (BMD) to create a personalized risk estimate. The results help guide decisions on whether a patient with low bone mass needs treatment to prevent future fractures.
How fracture risk assessment tools work
FRATs use algorithms to integrate patient data and predict fracture risk. Healthcare providers input patient information, and the tool, often calibrated for specific countries, provides an estimate.
Key inputs typically include:
- Demographics: Age, sex, race, height, and weight.
- Clinical factors: Previous fractures, parental hip fracture history, smoking, and heavy alcohol use.
- Secondary osteoporosis: Conditions increasing fracture risk like rheumatoid arthritis or type 1 diabetes.
- Medications: Long-term oral glucocorticoid use.
- Bone density (optional): Femoral neck BMD from a DXA scan for a more precise calculation.
The role of FRAX in clinical guidelines
FRAX has been incorporated into many national and international osteoporosis management guidelines since 2008. These guidelines often use FRAX scores to set thresholds for intervention. For example, the National Osteoporosis Foundation suggests considering medication for postmenopausal women and men over 50 with osteopenia if their 10-year major osteoporotic fracture risk is 20% or higher, or hip fracture risk is 3% or higher.
Using FRATs helps make decisions beyond just bone density. While osteoporosis is defined by a BMD T-score below -2.5, many fractures occur in people with osteopenia (T-scores between -1.0 and -2.5). FRATs help identify high-risk individuals within this group who could benefit from preventive treatment.
Comparison of FRAX and Garvan fracture calculators
| Feature | FRAX® Tool | Garvan Fracture Risk Calculator | QFracture Tool |
|---|---|---|---|
| Developer | WHO Collaborating Centre at the University of Sheffield. | Garvan Institute of Medical Research. | University of Sheffield. |
| Key Inputs | Age, sex, weight, height, prior fracture, parental hip fracture, smoking, glucocorticoid use, alcohol intake, rheumatoid arthritis, secondary osteoporosis, and femoral neck BMD (optional). | Age, sex, weight, number of previous fractures, falls in the last 12 months, and femoral neck BMD (optional). | Age, sex, ethnicity, BMI, medical conditions, medications, falls, alcohol, smoking, and history of falls. |
| Output | 10-year probability of hip fracture and major osteoporotic fracture. | 5- and 10-year absolute fracture risk. | 5- and 10-year absolute fracture risk, including hip and non-hip fractures. |
| Key Limitation | Does not account for recent fractures, multiple fractures, dose-dependent factors, or falls history, though newer versions address some. | May be less widely validated across diverse populations compared to FRAX. | Only applicable in the UK and does not use BMD data. |
| Geographic Scope | Widely used with country-specific models available for many nations. | Developed in Australia; applicability may vary by region. | Primarily used in the UK. |
Refinements and limitations of fracture risk assessment tools
FRATs like FRAX are valuable but have limitations. Early FRAX versions didn't account for factors like glucocorticoid dose, the number or recency of prior fractures, or a history of falls, all of which impact risk.
Ongoing research leads to refined models. The beta version of FRAXplus, for example, aims to include more detailed information such as recent fracture history, glucocorticoid dose, and number of falls. Some FRAX calculations also incorporate the Trabecular Bone Score (TBS), which assesses bone texture, to improve accuracy.
The importance of clinical context
FRATs provide a statistical probability and should not replace clinical judgment. They are tools for shared decision-making between patients and providers. A low FRAX score doesn't negate the risk posed by factors not fully captured, like multiple recent falls, which might still warrant treatment. Conversely, individuals with low bone density may need a FRAT to see if other risk factors increase their overall fracture probability to a level requiring intervention.
Conclusion
Fracture risk assessment tools, particularly FRAX, are essential for identifying individuals at high risk of osteoporotic fractures. By combining clinical factors and bone density data, these tools offer personalized risk estimates. While continually refined to address limitations, clinical judgment and patient discussion remain key to using these scores effectively for prevention and treatment. The development of tools like FRAXplus promises even more accurate and personalized risk prediction.
One authoritative outbound Markdown link: Explore the official FRAX tool to calculate a patient's fracture risk online.
