Is FRAX a Screening Tool? Understanding Its Role in Fracture Risk

According to the Bone Health & Osteoporosis Foundation, approximately 10.2 million adults in the U.S. have osteoporosis, a condition that increases fracture risk. The Fracture Risk Assessment Tool (FRAX) is a digital tool developed by the World Health Organization to help healthcare providers estimate an individual's 10-year probability of fracture. So, is FRAX a screening tool or something more?

Quick Summary

FRAX is a valuable screening tool that estimates an individual's 10-year risk of major osteoporotic or hip fracture based on a variety of clinical risk factors, with or without bone mineral density (BMD) information. It helps clinicians decide if further evaluation or treatment is needed.

Key Points

• Screening vs. Diagnostic: FRAX is a screening tool for risk assessment, not a definitive diagnosis of osteoporosis; diagnosis often requires a BMD test like DXA.

• 10-Year Probability: The tool calculates a patient's 10-year probability of a major osteoporotic fracture or a hip fracture based on several risk factors.

• Risk Factor Integration: FRAX considers numerous clinical risk factors, such as age, BMI, smoking status, and family history of hip fracture, providing a more comprehensive risk estimate.

• Guides Treatment Decisions: Clinicians use FRAX scores to decide if a patient with low bone mass (osteopenia) should undergo further testing or begin pharmacological treatment.

• Requires Clinical Judgment: The tool has limitations, such as not accounting for the dose of certain medications or the number of prior fractures, so it must be used with a clinician's expert judgment.

• Country-Specific Models: FRAX is calibrated to reflect the specific fracture and death rates of different countries to ensure local accuracy.

FRAX: A Comprehensive Fracture Risk Assessment

The Fracture Risk Assessment Tool (FRAX) is an algorithm developed by the WHO to estimate a patient's 10-year probability of a major osteoporotic fracture or hip fracture. It is used in patients aged 50 and older. It serves as a risk stratification tool to guide further assessment and treatment rather than a definitive diagnostic test.

How FRAX Works and Its Key Components

FRAX incorporates multiple independent risk factors for fracture prediction. Clinicians use patient data in a country-specific model, considering factors including age, sex, BMI, prior fractures, parental hip fracture history, smoking, glucocorticoid use, rheumatoid arthritis, other secondary causes, alcohol intake, and optionally, femoral neck BMD from a DXA scan. This provides a 10-year probability score for major osteoporotic and hip fractures.

The Clinical Role of FRAX

FRAX aids in identifying at-risk individuals and is not a diagnostic tool for osteoporosis. Its clinical uses include:

1. Identifying Treatment Candidates: FRAX helps determine if individuals with osteopenia meet thresholds for pharmacological treatment. The Bone Health and Osteoporosis Foundation provides specific risk thresholds for considering treatment in postmenopausal women and men over 50.
2. Guiding Further Assessment: FRAX can indicate the need for a BMD measurement via DXA scan, especially when risk is intermediate based on clinical factors. Adding BMD improves the risk estimate.
3. Cost-Effectiveness: Using FRAX can efficiently target high-risk individuals for screening and treatment.
4. Informing Clinical Judgment: FRAX is a support tool, not a substitute for a clinician's evaluation. Factors like recent or multiple fractures may suggest higher risk than the FRAX score alone.

FRAX vs. DEXA: A Comparison

FRAX and DXA are distinct tools often used together. Their differences are important for a complete osteoporosis assessment.

Feature	FRAX (Fracture Risk Assessment Tool)	DEXA (Dual-energy X-ray Absorptiometry)
Purpose	Predicts the 10-year probability of fracture based on clinical risk factors, with or without BMD data.	Measures bone mineral density (BMD) at specific sites to diagnose osteoporosis or osteopenia.
Method	A web-based or software algorithm.	A non-invasive imaging scan using a low-dose X-ray.
Input Data	Clinical risk factors plus optional femoral neck BMD.	Provides quantitative bone density measurements (T-scores and Z-scores).
Output	A percentage indicating the 10-year probability of major osteoporotic and hip fractures.	A T-score comparing bone density to a healthy young adult.
Main Role	Risk assessment and screening.	Diagnostic testing for osteoporosis and a key input for accurate FRAX calculation.

Limitations of the FRAX Tool

Clinicians should be aware of FRAX limitations. These include its lack of factors like glucocorticoid dose, number or recency of fractures, specific secondary osteoporosis types, or fall risk. Many factors are entered as yes/no, not reflecting dose effects. It primarily uses femoral neck BMD, which may not capture risk from low lumbar spine density. FRAX is for untreated patients only. It supports, but does not replace, clinical judgment.

Conclusion: The Verdict on FRAX as a Screening Tool

Is FRAX a screening tool? Yes, it is used for initial screening and risk assessment in postmenopausal women and men over 50. It is not a diagnostic tool for osteoporosis but helps identify patients needing further investigation or meeting treatment criteria. Despite limitations, it improves risk identification compared to BMD alone.

For more information on bone health and osteoporosis, visit the Bone Health and Osteoporosis Foundation at https://www.bonehealthandosteoporosis.org.

Frequently Asked Questions

Who should be assessed with FRAX?

The FRAX tool is intended for use in postmenopausal women and men aged 50 and older who have not yet received treatment for osteoporosis. It is particularly useful for assessing individuals with osteopenia to determine their overall fracture risk and need for intervention.

What information is needed to calculate a FRAX score?

To calculate a FRAX score, a clinician needs a patient's age, sex, BMI, and answers to questions about specific clinical risk factors, such as previous fractures, parental history of hip fracture, smoking, glucocorticoid use, and rheumatoid arthritis. Inputting the femoral neck bone mineral density from a DXA scan is optional but can improve accuracy.

Can I use FRAX if I'm already on osteoporosis medication?

No, the FRAX tool is not validated for patients who are already receiving pharmacological treatment for osteoporosis and should not be used in this population.

Is a FRAX score a diagnosis of osteoporosis?

No, a FRAX score is a fracture risk assessment, not a diagnosis of osteoporosis itself. A diagnosis of osteoporosis is typically confirmed with a DXA scan, which measures your bone mineral density.

What are the limitations of using FRAX?

Limitations include the tool’s binary classification of risk factors (yes/no), which doesn't account for dose-dependent effects, and its inability to factor in the risk of falling. It also doesn't consider the number of prior fractures, which is a key indicator of risk.

What happens if a patient's fracture risk is near the treatment threshold?

For patients whose FRAX score puts them near the therapeutic intervention threshold, clinicians must use their judgment. The score is a guide, and other factors, such as overall health and patient preferences, should be considered in the final decision-making process.

Does FRAX consider all factors that affect bone health?

No, FRAX does not account for certain variables known to impact bone health, such as vitamin D levels, physical activity, or the specific structural properties of the bone, requiring a clinician to consider these factors separately.