From the Guidelines
The FRAX score is a crucial tool in assessing the 10-year probability of major osteoporotic fractures or hip fractures, and a score indicating a 10-year risk of ≥20% for major osteoporotic fracture or ≥3% for hip fracture warrants osteoporosis treatment. The FRAX score evaluates risk by incorporating multiple factors including age, sex, BMI, previous fractures, parental hip fracture history, smoking status, glucocorticoid use, rheumatoid arthritis, secondary osteoporosis, and alcohol consumption 1. According to the 2022 update of the ACR Appropriateness Criteria for osteoporosis and bone mineral density, the FRAX tool is used to assess fracture risk in patients with low bone mass, and treatment is recommended for patients with a 10-year probability of a hip fracture ≥3% or a 10-year probability of a major osteoporosis-related fracture ≥20% based on FRAX 2.
When the FRAX score exceeds these thresholds, medications such as bisphosphonates (alendronate 70mg weekly, risedronate 35mg weekly), denosumab (60mg subcutaneously every 6 months), or teriparatide (20mcg subcutaneously daily) may be recommended, along with calcium (1000-1200mg daily) and vitamin D (800-1000 IU daily) supplementation. Key factors that influence the interpretation of FRAX scores include:
- Age: FRAX scores increase with age
- Sex: Women are at higher risk of osteoporotic fractures than men
- BMI: Lower BMI is associated with higher fracture risk
- Previous fractures: History of fractures increases fracture risk
- Glucocorticoid use: Long-term use of glucocorticoids increases fracture risk
- Rheumatoid arthritis: Presence of rheumatoid arthritis increases fracture risk
- Secondary osteoporosis: Presence of secondary osteoporosis increases fracture risk
- Alcohol consumption: Excessive alcohol consumption increases fracture risk
The FRAX tool is particularly valuable because it helps identify patients who would benefit from treatment even before they develop osteoporosis by bone density criteria alone, allowing for earlier intervention to prevent debilitating fractures. It's essential to note that FRAX calculations are most accurate when used with femoral neck bone mineral density measurements, though they can still provide useful estimates without BMD data 2.
From the Research
Frax Score Significance
The Frax score is a significant tool in assessing the 10-year probability of major osteoporotic fractures, including hip and vertebral fractures, in men and women aged 40 and over 3, 4, 5. The score is calculated based on clinical risk factors, such as prior fractures, parental hip fracture history, age, gender, body mass index, ethnicity, smoking, alcohol use, glucocorticoid use, and rheumatoid arthritis, as well as bone mineral density measurements 3, 5.
Key Findings
- The Frax score has been shown to be a useful tool in identifying individuals at increased risk for osteoporotic fractures, with a 10-year probability of hip fracture of 3% or greater, or a 10-year probability of major osteoporotic fracture of 20% or greater, being considered elevated 3, 4, 5.
- Studies have demonstrated that the Frax score is strongly predictive of overall fracture risk, with a mean sensitivity of 10.25% and specificity of 97.02% for major osteoporotic fractures, and a mean sensitivity of 45.70% and specificity of 84.70% for hip fractures 6.
- The Frax score has limitations, including the fact that it may not capture all relevant risk factors, such as frequent falls, and may not be applicable to all populations, such as those with secondary osteoporosis 3, 5.
- A hybrid system that combines femoral neck and lumbar spine bone density measurements has been shown to improve fracture risk prediction, particularly in cases where there is spine-hip discordance 7.
Clinical Applications
- The Frax score can be used to guide treatment decisions, with individuals having a Frax score above the treatment threshold being considered candidates for pharmacological therapy for osteoporosis 3, 5.
- The Frax score can also be used to monitor the effectiveness of treatment and to adjust treatment plans as needed 5.
- Clinicians should be aware of the limitations of the Frax score and use clinical judgment when interpreting the results, taking into account additional risk factors and individual patient characteristics 3, 5.