Who should undergo Dual-Energy X-ray Absorptiometry (DEXA) measurements?

DEXA Screening Recommendations

DEXA scanning should be performed in all women aged 65 years and older and men aged 70 years and older, with earlier screening only for those with significant risk factors for osteoporosis. 1, 2

Who Should Undergo DEXA Screening

Universal Screening:

• Women aged 65 years and older
• Men aged 70 years and older

Risk-Based Screening (Earlier Screening):

Individuals younger than the universal screening age with the following risk factors:

1. Postmenopausal women with:

   • History of fragility fracture
   • Body weight less than 127 lb (58 kg)
   • Parental history of hip fracture
   • Current smoking
   • Chronic glucocorticoid use (≥5 mg prednisone daily for ≥3 months)
   • Height loss >4 cm (>1.5 inches)
   • Early menopause/estrogen deficiency

2. Men aged 50-69 years with:

   • History of fragility fracture
   • Chronic glucocorticoid use
   • Hypogonadism
   • Height loss ≥4 cm

3. Special populations requiring screening regardless of age:

   • Patients with spinal cord injuries (as soon as medically stable)
   • Patients on androgen deprivation therapy for prostate cancer
   • Patients on aromatase inhibitors for breast cancer
   • HIV-infected postmenopausal women and men ≥50 years
   • Patients with chronic inflammatory conditions
   • Patients with medical conditions associated with bone loss (e.g., hyperparathyroidism)
   • Transgender individuals (based on hormone therapy compliance, gonadal removal, and other risk factors)

Screening Intervals

• Initial screening: Based on age and risk factors as outlined above
• Standard follow-up interval: Every 2 years
• Shorter intervals (1 year): For patients:
  • Initiating osteoporosis therapy
  • At high risk for rapid bone loss
  • After cessation of pharmacologic therapy

Technical Considerations for DEXA

• Scans should be performed at facilities with skilled technologists who have conducted precision assessments
• Follow-up scans should be performed on the same machine with the same software and positioning
• Changes in BMD should be evaluated using absolute values (g/cm²), not T-scores or Z-scores
• Only changes that meet or exceed the least significant change (LSC) should be considered significant

Diagnostic Criteria

• Normal: T-score > -1.0
• Osteopenia/Low bone mass: T-score between -1.0 and -2.4
• Osteoporosis: T-score ≤ -2.5 or fragility fracture regardless of T-score

Common Pitfalls to Avoid

1. Inappropriate screening intervals: Avoid unnecessary frequent testing that doesn't meet the recommended intervals.

2. Using T-scores for young patients: For children, adolescents, premenopausal women, and men under 50, Z-scores should be used instead of T-scores.

3. Comparing T-scores between scans: Serial measurements should compare absolute BMD values, not T-scores.

4. Inconsistent scanning technique: Follow-up scans should use the same machine, software, and positioning as the initial scan.

5. Relying solely on BMD for treatment decisions: In patients with osteopenia, fracture risk assessment tools like FRAX should be used to guide treatment decisions.

6. Ignoring clinical risk factors: BMD testing alone may underestimate fracture risk in conditions like glucocorticoid-induced osteoporosis and type 2 diabetes.

By following these evidence-based recommendations for DEXA screening, clinicians can identify patients at risk for osteoporotic fractures and initiate appropriate interventions to reduce morbidity and mortality associated with fragility fractures.