What is the role of the FRAX (Fracture Risk Assessment) tool in managing a patient with osteopenia, and how is it used to guide treatment decisions?

FRAX Tool for Osteopenia Treatment

For patients with osteopenia (T-score between -1.0 and -2.5), use the WHO FRAX calculator to determine 10-year fracture probability, and initiate pharmacologic treatment when the 10-year hip fracture risk is ≥3% or major osteoporotic fracture risk is ≥20%. 1, 2

How to Access and Use the FRAX Tool

Step 1: Access the Calculator

• Use the online WHO FRAX calculator (available as a web-based tool or integrated into DXA reporting software) for untreated postmenopausal women and men aged 40-90 years 2, 3

Step 2: Enter Required Patient Data

Input the following variables into the calculator 2, 3:

• Age (40-90 years)
• Sex (male or female)
• Body mass index (BMI in kg/m²)
• Femoral neck BMD T-score (optional but improves accuracy) 4
• Prior fragility fracture (yes/no)
• Parental hip fracture history (yes/no)
• Current tobacco smoking (yes/no)
• Glucocorticoid use (yes/no - currently taking or has taken oral glucocorticoids for >3 months)
• Rheumatoid arthritis (yes/no)
• Secondary osteoporosis (yes/no - conditions like type 1 diabetes, hyperthyroidism, chronic liver disease)
• Alcohol consumption (yes/no - 3 or more units daily)

Step 3: Interpret the Results

The calculator generates two key outputs 1, 5:

• 10-year probability of hip fracture
• 10-year probability of major osteoporotic fracture (hip, clinical vertebral, forearm, or humerus combined)

Treatment Decision Thresholds

Standard U.S. Treatment Thresholds

Initiate pharmacologic therapy when 6, 2:

• 10-year hip fracture risk ≥3%, OR
• 10-year major osteoporotic fracture risk ≥20%

These thresholds represent cost-effective intervention points in the United States 6

Risk Stratification for Medication Selection

Beyond the binary treat/don't treat decision, categorize patients to guide medication choice 1, 2:

Very High Risk (consider anabolic therapy first) 1, 2:

• Major osteoporotic fracture risk ≥30%, OR
• Hip fracture risk ≥4.5%, OR
• Recent fracture (within past 2 years), OR
• Fracture while on osteoporosis therapy, OR
• Multiple risk factors combined

High Risk (consider antiresorptive therapy) 1, 2:

• Major osteoporotic fracture risk 20-30%, OR
• Hip fracture risk 3-4.5%

Critical Adjustments and Special Populations

Glucocorticoid Users

For patients taking prednisone >7.5 mg/day (or equivalent), manually adjust the calculated FRAX scores 1, 2, 4:

• Multiply major osteoporotic fracture risk by 1.15
• Multiply hip fracture risk by 1.2

This adjustment accounts for dose-dependent effects not captured in the base algorithm's yes/no glucocorticoid input 1, 2

Additional Risk Stratification for Osteopenia Patients

In patients with osteopenia and height loss, obtain 6:

• Plain radiographs of thoracic and lumbar spine, OR
• DXA with vertebral fracture assessment software

Rationale: Clinically silent vertebral fractures are common and automatically trigger pharmacologic therapy regardless of FRAX score or BMD 6

Reassessment Intervals

For Patients NOT on Treatment

• Every 1-3 years for those on glucocorticoids 2, 4
• Every 1-2 years for those with low-moderate fracture risk 1
• Earlier reassessment (within 1 year) if new risk factors develop 2

For Patients ON Treatment

• Reassess every 1-2 years to determine if BMD is stable, improving, or declining 1

Essential Limitations and Pitfalls

When NOT to Use FRAX

Do not use FRAX in 1, 4:

• Adults <40 years of age
• Children
• Patients already on osteoporosis therapy (FRAX is validated only for untreated patients) 3, 7

For younger adults <40 years on glucocorticoids, use clinical risk assessment with BMD Z-scores instead 1

What FRAX Does NOT Capture

Be aware that FRAX has important blind spots 1, 2, 4:

• Fall history or frailty - not incorporated into the algorithm
• Dose-dependent effects - only captures yes/no for glucocorticoids and alcohol, not actual doses
• Lumbar spine BMD - only uses femoral neck BMD
• Trabecular bone score - not included
• Multiple prior fractures - only captures yes/no for prior fracture, not the number

Population-Specific Concerns

• FRAX may underestimate risk in HIV-infected patients and has not been validated in this population 6
• Race-specific calculators may lead to disparities in treatment recommendations among persons with otherwise identical risk profiles 2, 4

Mandatory Concurrent Actions

Regardless of FRAX Score

All patients with osteopenia require 6:

• Work-up for secondary causes of bone loss (vitamin D deficiency, hyperparathyroidism, hyperthyroidism, celiac disease, etc.)
• Non-pharmacologic interventions:
  • Calcium 1000-1500 mg daily
  • Vitamin D 800-1000 IU daily
  • Weight-bearing exercise 30 minutes at least 3 days per week
  • Smoking cessation
  • Alcohol limitation
  • Fall prevention strategies

Treatment of Secondary Causes

If secondary causes are identified (particularly vitamin D deficiency with 25[OH]D <15 ng/mL), address these specifically before or concurrent with osteoporosis pharmacotherapy 6