What is the recommended approach for bone density screening and treatment for individuals at risk of osteoporosis?

Bone Density Screening for Osteoporosis

All women aged 65 years and older should undergo routine bone density screening with DXA of the hip and lumbar spine, regardless of risk factors. 1, 2

Screening Recommendations by Age and Sex

Women ≥65 Years

• Screen all women routinely with dual-energy x-ray absorptiometry (DXA) at the femoral neck and lumbar spine 1, 2
• This is a Grade B recommendation with strong evidence that screening and treatment reduces vertebral, nonvertebral, and hip fractures 1, 2

Postmenopausal Women 60-64 Years

• Screen if 10-year fracture risk equals or exceeds that of a 65-year-old white woman without additional risk factors (9.3% 10-year risk) 1
• Use a 2-step approach: first identify risk factors, then use FRAX or another validated risk assessment tool to calculate fracture probability 1
• Key risk factors include: 1, 3
  • Low body weight (<70 kg or <127 lbs) - single best predictor of low bone density 1, 3
  • No current estrogen use 1
  • Previous fragility fracture 3
  • Parental history of hip fracture 1
  • Current cigarette smoking 1
  • Excess alcohol consumption 1
  • Long-term glucocorticoid therapy (≥7.5 mg prednisone equivalent daily for ≥6 months) 3, 4

Postmenopausal Women <60 Years

• Do not screen routinely unless multiple high-risk factors are present 1, 3
• The balance of benefits and harms is too close to justify routine screening in this age group 1

Men

• Screen men aged 70 years and older with DXA if they are candidates for drug therapy 1
• For men aged 50-69 years, screen only if significant risk factors are present (prior fracture, glucocorticoid use, androgen deprivation therapy) 1
• Evidence for screening men is substantially weaker than for women 1

Optimal Screening Method

DXA at the femoral neck is the best predictor of hip fracture and the gold standard for diagnosis 1, 3

Standard DXA Protocol

• Measure two sites: lumbar spine (L1-L4) and total hip/femoral neck 1
• If lumbar spine is unreliable due to fracture, severe osteoarthritis, or spondylosis, exclude up to 2 vertebral levels 1
• If >2 vertebral levels must be excluded, substitute the contralateral hip 1
• For hyperparathyroidism specifically, measure distal one-third radius of non-dominant arm 1

Alternative Technologies

• Peripheral DXA, quantitative ultrasonography, and peripheral quantitative CT can identify women at higher short-term fracture risk 1
• However, these require further validation compared to central DXA and should not replace it for diagnosis 1

Risk Assessment Tools

FRAX is the most studied and validated fracture risk assessment tool 1

FRAX Characteristics

• Predicts 10-year probability of hip fracture or major osteoporotic fracture (MOF) 1
• Can be used with or without BMD, but accuracy improves when BMD is included 1
• Country-specific versions calibrated using local fracture incidence and mortality data 1
• Four US versions available calibrated for different racial/ethnic groups 1
• Incorporated into 120 guidelines worldwide and FDA-approved for integration into DXA software 1

Alternative Risk Tools

• Osteoporosis Risk Assessment Instrument (ORAI): sensitivity 93.3%, specificity 46.4% for identifying low BMD 5
• Fracture Risk Calculator (FRC) and Garvan Fracture Risk Calculator are alternatives 1
• Osteoporosis Self-assessment Tool (OST) requires fewer inputs but is less comprehensive 1

Screening Intervals

Minimum 2 years between repeat DXA scans due to precision limitations of the technology 1, 2, 3

Individualized Re-screening Strategy

• Higher-risk patients (older age, lower baseline T-score, multiple risk factors): consider screening every 2 years 1, 2
• Normal bone density or mild osteopenia: repeat DXA in 2-3 years 3
• Patients on treatment: repeat DXA in 1-2 years to monitor treatment effectiveness 3
• Longer intervals (>2 years) may be adequate for identifying new cases in lower-risk women 1

Treatment Considerations

All patients diagnosed with osteoporosis should receive calcium 1000-1200 mg daily and vitamin D 800-1000 IU daily 2, 4

Pharmacologic Treatment Indications

• T-score ≤-2.5 at femoral neck, total hip, or lumbar spine 1
• History of osteoporotic fracture (supersedes any DXA measurement) 1
• 10-year fracture risk calculated by FRAX meeting treatment thresholds 3

Treatment Options

• Bisphosphonates (e.g., alendronate): first-line therapy with strongest evidence for fracture reduction (40-50% risk reduction) 1, 2, 6
• Denosumab (Prolia): FDA-approved for postmenopausal women at high fracture risk, men with osteoporosis, glucocorticoid-induced osteoporosis 4
• Selective estrogen receptor modulators, calcitonin, or hormone replacement therapy based on individual risk-benefit profile 1
• Clinicians must review relative benefits and harms of all treatment options with patients to facilitate informed choice 1

Race and Ethnicity Considerations

African-American women have higher average BMD than white women at any given age and lower fracture incidence 1

• Asian, Black, and Hispanic populations have lower fracture incidence than white populations despite sometimes having lower BMD 1
• Differences in fracture risk among racial/ethnic groups are not fully explained by BMD alone and likely involve social, environmental, and clinical factors 1
• Use race/ethnicity-specific FRAX calculators when available 1

Critical Pitfalls to Avoid

Diagnostic Errors

• Do not diagnose osteoporosis based on peripheral bone density testing alone - requires central DXA confirmation 1
• Likelihood of osteoporosis diagnosis varies by site tested, number of sites, densitometer brand, and reference range used 1
• Exclude vertebral levels with fracture or severe degenerative changes that falsely elevate BMD 1

Treatment Discontinuation Risks

• Never stop, skip, or delay denosumab without transitioning to alternative therapy - risk of multiple vertebral fractures increases dramatically after discontinuation 4
• Patients stopping any osteoporosis medication require close monitoring and transition to alternative therapy 4

Special Populations Requiring Caution

• Patients with advanced chronic kidney disease (eGFR <30 mL/min) are at high risk for severe hypocalcemia with denosumab 4
• Evaluate for chronic kidney disease-mineral bone disorder (CKD-MBD) before initiating denosumab in these patients 4
• Treatment should be supervised by a provider with CKD-MBD expertise 4

Infection and Dental Risks

• Examine mouth and address dental issues before starting denosumab - risk of osteonecrosis of the jaw 4
• Patients on denosumab have increased risk of serious infections requiring hospitalization 4
• Maintain good oral hygiene and inform dentist of denosumab use before any dental procedures 4

When to Stop Screening

No data exist to determine appropriate age to stop screening 1

• Few data available on osteoporosis treatment effectiveness in women >85 years 1
• Decision should be individualized based on life expectancy, functional status, and patient preferences for treatment