How often should a Dual-Energy X-ray Absorptiometry (DEXA) scan be performed?

DEXA Scan Frequency Recommendations

For most patients, DEXA scans should be repeated every 2 years, with annual scanning reserved for high-risk individuals on bone-depleting medications or with conditions causing accelerated bone loss. 1, 2

Standard Screening and Follow-Up Intervals

Initial Screening

• All women ≥65 years should undergo baseline DEXA scanning 3
• Postmenopausal women <65 years with risk factors (history of fragility fracture, weight <127 lbs, medications/diseases causing bone loss, parental history of hip fracture) should be screened 3
• Men ≥70 years should be considered for screening, though evidence is less robust 4

Routine Follow-Up Based on Baseline Results

• Normal BMD or mild osteopenia (T-score >-2.0): Repeat every 2 years 2, 5
• Moderate to severe osteopenia (T-score ≤-2.0): Repeat every 2 years 5
• Established osteoporosis on treatment: Repeat every 2 years for stable patients 1

Critical principle: Never scan more frequently than annually, as intervals <1 year rarely provide clinically meaningful information due to slow bone density changes and measurement variability. 1, 2, 5

High-Risk Patients Requiring Annual Monitoring

The following patients warrant annual DEXA scans due to accelerated bone loss risk:

Medication-Related Risk Factors

• Glucocorticoid therapy for >3 months 1, 2, 5
• Aromatase inhibitors for breast cancer 2, 5
• Androgen deprivation therapy for prostate cancer 1, 2, 5
• Anticonvulsants, chronic heparin, or other bone-depleting medications 2

Medical Conditions Accelerating Bone Loss

• Chronic renal failure 1, 2, 5
• Inflammatory arthritis (rheumatoid arthritis) 1, 2, 5
• Eating disorders 1, 2
• Gastrointestinal malabsorption syndromes 2, 5
• Organ transplantation 2
• Hypogonadal men or surgically/chemotherapeutically induced castration 1

Special Populations

• Spinal cord injury patients: 1-2 year intervals at total hip, distal femur, and proximal tibia after minimum 12 months of therapy 1
• Female athletes with risk factors for Female Athlete Triad: every 1-2 years 2
• Advanced cirrhosis or patients awaiting liver transplantation: annually 2

Situations Requiring Immediate Repeat Testing

Regardless of scheduled interval, perform DEXA scanning immediately if:

• New fragility fracture occurs 1
• New risk factors develop (hyperparathyroidism, malabsorption, initiation of bone-depleting medications) 1
• Monitoring prior to temporary cessation of bisphosphonate therapy 1

Critical Technical Considerations to Ensure Accuracy

Measurement Consistency

• Always use the same DXA machine for follow-up scans to ensure accurate comparison 1, 2, 5
• Compare BMD values (g/cm²), not T-scores, between serial scans for more accurate assessment of changes 1, 2, 5

Common Pitfalls to Avoid

• Lumbar spine degenerative changes, osteoarthritis, and other artifacts commonly cause spurious increases in BMD values at the spine, potentially masking true bone loss 1, 2
• Failing to recognize new risk factors that warrant earlier follow-up regardless of previous schedule 1
• Scanning intervals <1 year should be avoided as they rarely provide clinically meaningful information 1, 2, 5

Evidence-Based Intervals for Low-Risk Patients

For patients with initially normal bone density and no risk factors, longer intervals may be appropriate:

• Transition to osteoporosis occurs over approximately 17 years for those with normal BMD 1
• Repeating BMD testing at intervals of 4-8 years does not result in additional accuracy in predicting fractures in patients with initially normal bone density 1
• However, the standard recommendation remains every 2 years for practical clinical monitoring 2