DEXA Scanning Recommendations
DEXA scanning of the lumbar spine and hip is the gold standard for osteoporosis screening and should be performed in all women ≥65 years, postmenopausal women <65 years with risk factors, men ≥70 years, and any adult with specific high-risk conditions including glucocorticoid therapy, endocrine disorders, or prior fragility fracture. 1, 2, 3
Primary Screening Indications
Standard Population Screening
- All women ≥65 years should undergo DEXA screening regardless of risk factors 1, 2, 4
- Postmenopausal women <65 years with clinical risk factors for fracture require screening 1, 3, 4
- Men ≥70 years should be screened according to Bone Health and Osteoporosis Foundation guidelines 4
- Men 50-70 years with risk factors warrant screening, though USPSTF evidence is insufficient for routine screening in all men 4
High-Risk Conditions Requiring Earlier Screening
- Glucocorticoid therapy ≥5 mg prednisone equivalent daily for ≥3 months mandates DEXA scanning regardless of age 1, 2
- Endocrine disorders affecting bone metabolism (hyperthyroidism, hypogonadism, Hashimoto's thyroiditis) require screening 2
- Young adults (20-50 years) with hypogonadism (including Klinefelter syndrome) should undergo early screening rather than waiting until standard age thresholds 5
- History of hysterectomy at young age increases risk due to premature estrogen deficiency 3
- Prior fragility fracture is diagnostic of osteoporosis even without DEXA confirmation 6, 4
Additional Risk Factors Prompting Screening
- Body weight <127 lb (58 kg) 2
- Parental history of hip fracture 2
- Prolonged immobilization 2
- Malabsorption or malnutrition 2
- Chronic inflammatory disease 6
- Untreated premature menopause 6
Recommended Scanning Protocol
Standard Imaging Approach
- DXA of lumbar spine and bilateral hips is the primary recommended modality (rated 9/9 for appropriateness) 1, 5
- Both sites should be scanned routinely as they provide complementary information 7, 8
- Hip DXA is most reliable for predicting hip fracture risk 7
- Spine DXA is most sensitive for monitoring treatment response 7
Special Circumstances
- Patients with advanced degenerative spine changes, scoliosis, or ankylosing spondylitis: Consider DXA distal forearm or quantitative CT (qCT) of lumbar spine and hip as alternatives 1
- DEXA can be falsely elevated by osteophytes and degenerative facet disease in >81% of spuriously elevated measurements 1
- qCT or opportunistic CT may be more accurate than DEXA in patients with spinal degeneration 1
- Hounsfield unit (HU) values >160 indicate low osteoporosis risk, while HU <110 correlate with osteoporosis 1
Vertebral Fracture Assessment (VFA)
- VFA should be added to DEXA for patients with T-score <-1.0 AND one or more of: 1, 2
- Females ≥70 years or males ≥80 years
- Historical height loss >4 cm (>1.5 inches)
- Self-reported but undocumented prior vertebral fracture
- Glucocorticoid therapy as defined above
- VFA and DEXA are complementary and performed concomitantly for point-of-care service 1
Interpretation of Results
Diagnostic Thresholds
- T-score ≤-2.5 confirms osteoporosis diagnosis 6, 4, 8
- T-score between -1.0 and -2.5 indicates osteopenia; use FRAX to guide treatment decisions 2, 4
- Vertebral fractures are diagnostic of osteoporosis even if BMD is not in osteoporotic range 6
Age-Specific Reporting
- T-scores should be used for postmenopausal women and men ≥50 years 2
- Z-scores (not T-scores) should be reported for premenopausal women and men <50 years 2
- Z-scores ≤-2.0 are considered below expected age range 2
Glucocorticoid-Induced Osteoporosis Exception
- Fractures occur at higher BMD levels in glucocorticoid-induced osteoporosis 6
- Treatment should be considered at T-score <-1.5 (not -2.5) for patients on chronic glucocorticoids 6
Follow-Up Monitoring Schedule
Treatment Monitoring
- Every 1-2 years for patients on glucocorticoid therapy 2
- Every 1-2 years if osteoporosis is present or treatment initiated 5
- Every 2 years for monitoring untreated patients with risk factors 2
- Every 2 years if initial scan shows osteopenia or osteoporosis 3
Risk-Stratified Monitoring
- Every 2-3 years if initial BMD shows osteopenia 5
- Every 2-5 years if initial BMD is normal 5
- Closer to 2-year intervals is prudent for progressive conditions like Klinefelter syndrome 5
Treatment Thresholds
Pharmacologic Treatment Indications
- T-score ≤-2.5 warrants treatment 2, 4
- T-score between -1.0 and -2.5 with FRAX 10-year probability ≥3% for hip fracture OR ≥20% for major osteoporotic fracture 9, 4
- Any fragility fracture regardless of DEXA results 2, 4
- T-score <-1.5 for glucocorticoid-induced osteoporosis 6
First-Line Treatment
- Oral bisphosphonates are first-line therapy 6, 4
- Parenteral therapy (denosumab) if bisphosphonates contraindicated or not tolerated 6, 4
- Anabolic agents (teriparatide, abaloparatide, romosozumab) for very high risk or previous vertebral fractures 4
Prevention Recommendations
Calcium and Vitamin D Supplementation
- Ages 19-50: 1,000 mg calcium, 600 IU vitamin D daily 2
- Ages 51-70: 1,200 mg calcium, 600 IU vitamin D daily 2
- Ages 71+: 1,200 mg calcium, 800 IU vitamin D daily 2
Lifestyle Modifications
Critical Pitfalls to Avoid
- Do not delay screening in high-risk young adults (e.g., Klinefelter syndrome, hypogonadism) until standard age thresholds 5
- Do not rely solely on spine DEXA in patients with degenerative changes; consider alternative sites or modalities 1
- Do not use standard T-score thresholds for glucocorticoid-induced osteoporosis; use -1.5 instead of -2.5 6
- Do not stop denosumab without transition to alternative therapy due to rebound multiple-fracture risk 9
- Do not require DEXA before initiating treatment in patients >65 years with clear indications, as vast majority will have T-score ≤-1.5 6
- Investigate secondary causes or non-compliance if patient fails to improve BMD on therapy or sustains incident fracture 9