What is the recommended approach for assessing and managing osteoporosis in an older adult with risk factors, using the FRAX (Fracture Risk Assessment Tool) score?

FRAX Score: Assessment and Management of Osteoporosis Risk

What FRAX Is and How to Use It

FRAX is the World Health Organization's fracture risk calculator that estimates 10-year probability of hip fracture and major osteoporotic fracture (spine, hip, wrist, or humerus) using easily obtainable clinical information, and it should be used in all postmenopausal women and men aged 40-90 years who are treatment-naïve to guide screening and treatment decisions. 1

Key Input Variables

FRAX requires the following clinical information:

• Age, sex, body mass index (BMI) 1
• Prior fragility fracture history 2
• Parental hip fracture history 2
• Current tobacco smoking 2
• Glucocorticoid use (≥5 mg prednisone daily for ≥3 months) 2
• Rheumatoid arthritis 2
• Secondary osteoporosis causes 2
• Alcohol consumption (≥3 units daily) 2
• Femoral neck BMD T-score (optional but improves accuracy) 1, 2

The tool is freely accessible at www.shef.ac.uk/FRAX/ and has been extensively validated in large U.S. cohorts. 1

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Treatment Thresholds: When to Initiate Pharmacotherapy

Pharmacologic treatment is recommended when FRAX demonstrates ≥3% 10-year hip fracture risk OR ≥20% 10-year major osteoporotic fracture risk. 3, 4, 2

Automatic Treatment Indications (Regardless of FRAX Score)

These conditions mandate treatment consideration even without calculating FRAX:

• Any prior fragility fracture (overrides all FRAX thresholds) 3, 4
• BMD T-score ≤-2.5 at hip or spine in postmenopausal women or men ≥50 years 3
• Very high fracture risk criteria: Prior osteoporotic fracture OR T-score ≤-3.5 OR FRAX major osteoporotic fracture ≥30% or hip ≥4.5% 1, 3

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Screening Recommendations by Age and Sex

Women

All women aged ≥65 years should be screened with DXA regardless of risk factors. 1

Women aged 50-64 years should be screened if their FRAX score equals or exceeds that of a 65-year-old white woman with no risk factors (9.3% 10-year major osteoporotic fracture risk). 1

Examples of younger women meeting this threshold include:

• 50-year-old current smoker with BMI <21 kg/m², daily alcohol use, and parental fracture history 1
• 55-year-old woman with parental fracture history 1
• 60-year-old woman with BMI <21 kg/m² and daily alcohol use 1

Men

Evidence is insufficient to recommend routine screening in men, though the same treatment thresholds (≥3% hip fracture or ≥20% major osteoporotic fracture) can be applied when screening is performed. 1

Men most likely to benefit would have 10-year risks equal to or greater than 65-year-old white women with no additional risk factors. 1

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Critical Adjustments for Glucocorticoid Users

For patients on prednisone >7.5 mg/day, manually adjust FRAX scores by multiplying major osteoporotic fracture risk by 1.15 and hip fracture risk by 1.2. 1, 4, 2

Glucocorticoid-Specific Risk Stratification

For adults on glucocorticoids ≥2.5 mg/day for >3 months:

• Very high risk: High-dose glucocorticoids ≥30 mg/day for >30 days OR cumulative doses ≥5 g/year 1
• Initial assessment should include FRAX (age ≥40 only), BMD with vertebral fracture assessment (VFA) or spine x-rays 1
• Reassess BMD with VFA every 1-2 years during treatment 1

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Risk Stratification for Treatment Selection

Very High Risk (Consider Anabolic Therapy First)

• Prior osteoporotic fracture(s) 1, 3
• BMD T-score ≤-3.5 1, 3
• FRAX major osteoporotic fracture ≥30% or hip ≥4.5% 1, 3
• High-dose glucocorticoids ≥30 mg/day for >30 days 1

For very high risk patients, anabolic agents (teriparatide, abaloparatide) are conditionally recommended over antiresorptive agents. 1

High Risk (Consider Antiresorptive Therapy)

• BMD T-score ≤-2.5 but >-3.5 1
• FRAX major osteoporotic fracture ≥20% but <30% or hip ≥3% but <4.5% 1

For high risk patients aged ≥40 years, denosumab or PTH/PTHrP are conditionally recommended over bisphosphonates. 1

Moderate Risk

• FRAX major osteoporotic fracture ≥10% and <20%, hip >1% and <3% 1
• BMD T-score between -1.0 and -2.4 1

For moderate risk, oral or IV bisphosphonates, denosumab, and PTH/PTHrP are all conditionally recommended. 1

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Screening Intervals and Reassessment

Repeat BMD testing every 1-2 years if not on treatment; annually if on treatment. 3

A minimum of 2 years is needed to reliably measure BMD change due to testing precision limitations, though longer intervals may be needed to improve fracture risk prediction. 1

Reassess FRAX annually or with significant clinical changes. 3

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Critical Limitations and Pitfalls to Avoid

When NOT to Use FRAX

• Patients already on osteoporosis treatment (FRAX is validated only for treatment-naïve patients) 4, 5, 6
• Adults <40 years (use BMD Z-scores instead) 1, 4
• Patients with prior fragility fracture (they already meet treatment criteria) 3, 4

Important FRAX Limitations

• Does not account for dose-dependent glucocorticoid effects beyond yes/no (requires manual adjustment) 1, 4, 2
• Does not incorporate fall history, frailty, or number/timing of fractures 1, 4
• Does not use lumbar spine BMD or trabecular bone score 2
• May underestimate risk in non-white populations 2
• Binary inputs miss nuances (e.g., one prior fracture vs. multiple fractures treated identically) 4

Common Clinical Errors

Do not ignore prior fractures—even a single fragility fracture overrides FRAX thresholds and mandates treatment consideration. 3, 4

Do not forget to check hip-specific risk separately—the major osteoporotic fracture risk alone is insufficient, as hip fracture risk ≥3% is an independent treatment indication. 3, 4

Do not assume all patients with the same FRAX score have equal risk—a 55-year-old with 8.5% risk has different implications than a 75-year-old with the same score. 3

Do not use FRAX for monitoring treatment response—it cannot assess fracture risk reduction in treated patients, though it may still guide decisions about continuing or stopping treatment. 6

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First-Line Treatment Approach

Non-Pharmacologic Interventions (All Patients)

• Calcium supplementation: 1,000-1,200 mg daily 3
• Vitamin D supplementation: 800-1,000 IU daily 3
• Weight-bearing exercise: ≥30 minutes, 3 days per week 3

Pharmacologic Treatment

Initiate bisphosphonate therapy (alendronate) as first-line for high-risk patients, which reduces spine and hip fractures by approximately 50% over 3 years. 3

For very high-risk patients, consider anabolic therapy first (teriparatide, abaloparatide). 1, 3

Sequential therapy is essential—plan for transition after denosumab, romosozumab, or PTH/PTHrP to prevent rebound bone loss and vertebral fractures. 1

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Race and Ethnicity Considerations

FRAX provides race-specific calculators for white, black, Asian, and Hispanic populations in the United States. 1

Estimated fracture risks in non-white women are generally lower than those for white women of the same age, though FRAX may still underestimate risk in these populations. 1, 2

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Screening Tests: DXA vs. Quantitative Ultrasonography

DXA of the hip and lumbar spine is the gold standard for screening, as current diagnostic and treatment criteria rely exclusively on DXA measurements. 1

Quantitative ultrasonography of the calcaneus predicts fractures as effectively as DXA but cannot be used for diagnosis or treatment decisions, as criteria based on ultrasonography have not been defined. 1

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Clinical Judgment and Patient Values

When FRAX scores fall near treatment thresholds (e.g., 8.5% major osteoporotic fracture risk), consider additional factors including hip-specific risk, prior fractures, BMD T-score, menopausal status, remaining lifespan, and patient preferences. 1, 3

Treatment benefits emerge 18-24 months after initiation, so consider remaining lifespan when screening patients with significant illness. 1