What is the FRAX Calculator?
The Fracture Risk Assessment Tool (FRAX) is a diagnostic tool developed by the World Health Organization (WHO) to evaluate the 10-year probability of bone fractures in patients. It specifically calculates the risk of a major osteoporotic fracture (spine, forearm, hip, or shoulder) and the specific risk of a hip fracture.
How Risk Factors Influence Your Score
This calculator evaluates several key clinical risk factors that impact bone density and structural integrity:
- Age: Risk increases significantly as you age, particularly after 65.
- Body Mass Index (BMI): Lower body weight (low BMI) is a significant risk factor for bone loss.
- Glucocorticoids: Long-term use of steroid medications like Prednisone can weaken bone tissue.
- Previous Fractures: A history of "fragility fractures" (broken bones from a minor fall) is the strongest predictor of future events.
- Secondary Osteoporosis: Conditions like Type 1 Diabetes or untreated hyperthyroidism increase risk.
Understanding Your Results
Typically, a 10-year risk of a major osteoporotic fracture greater than 20% or a hip fracture risk greater than 3% is considered a threshold where clinicians may recommend pharmacological intervention (bone-building or bone-preserving medications).
Practical Examples
Example A: A 70-year-old female weighing 55kg (low BMI) with a parent who suffered a hip fracture. Even without a personal history of fractures, her risk may exceed 15% due to genetics and weight.
Example B: A 50-year-old male who smokes and uses glucocorticoids for asthma. His risk might be relatively low now (e.g., 4%), but his "preventative" score highlights factors he can change to avoid high risk later in life.