When to Request a DEXA Scan
DEXA scans should be performed in all women 65 years and older and men 70 years and older, regardless of clinical risk factors, as well as in younger postmenopausal women and men ≥50 years with risk factors for fracture. 1
Standard Screening Recommendations
Age-Based Screening
- Women ≥65 years
- Men ≥70 years
- Postmenopausal women <65 years with risk factors
- Men 50-69 years with risk factors
Risk Factors That Warrant Earlier Screening
- Previous fragility fracture
- Long-term oral glucocorticoid therapy (≥5 mg prednisone daily for ≥3 months)
- Low body weight (<127 lb/58 kg)
- Parental history of hip fracture
- Current smoking
- Excessive alcohol consumption
- Secondary causes of osteoporosis (see below)
- Height loss ≥4 cm (>1.5 inches)
- Early menopause (<45 years) or prolonged amenorrhea
- Rheumatoid arthritis
Special Populations Requiring DEXA
HIV-Infected Individuals
- All HIV-infected postmenopausal women
- HIV-infected men ≥50 years of age 1
- Consider HIV infection itself as a risk factor for low BMD
Patients with Specific Medical Conditions
- Spinal Cord Injury: As soon as medically stable, with follow-up at 1-2 year intervals 1
- Prostate Cancer: Men on androgen deprivation therapy (ADT) 1
- Transgender Individuals: Based on assessment of hormone therapy compliance, gonadal removal, and additional risk factors 1
Secondary Causes of Osteoporosis Requiring DEXA
- Endocrine disorders: Hyperparathyroidism, hypogonadism, hyperthyroidism
- Gastrointestinal disorders: Malabsorption syndromes, inflammatory bowel disease, celiac disease
- Hematologic disorders: Multiple myeloma, leukemia
- Rheumatologic disorders: Rheumatoid arthritis, ankylosing spondylitis
- Medications: Long-term glucocorticoids, anticonvulsants, aromatase inhibitors, GnRH agonists
Follow-Up DEXA Recommendations
- If initial results do not warrant treatment: Repeat every 2-5 years depending on proximity to treatment thresholds
- If on osteoporosis treatment: Follow-up BMD testing to monitor response to therapy
- If new fracture occurs or new risk factors develop: Repeat DEXA regardless of previous results
- Prior to temporary cessation of bisphosphonate therapy and during planned treatment interruption
Vertebral Fracture Assessment (VFA) Indications
VFA or standard radiography should be performed in:
- T-score < -1.0 with one or more of:
- Women ≥70 years or men ≥80 years
- Historical height loss >4 cm (>1.5 inches)
- Self-reported but undocumented prior vertebral fracture
- Long-term oral glucocorticoid therapy
Common Pitfalls to Avoid
Ignoring site-specific measurements: Distal forearm DEXA may be better for predicting distal radius fracture risk in elderly women than central DEXA 2
Artifacts affecting interpretation: Be aware that degenerative changes in the spine can falsely elevate BMD measurements
Inappropriate use in young patients: DEXA scans in younger individuals without risk factors are generally not indicated as fracture risk is low
Failure to recognize limitations: DXA may underestimate fracture risk in certain conditions (e.g., glucocorticoid-induced osteoporosis, type 2 diabetes)
Overlooking the need for vertebral fracture assessment: Some patients with BMD above treatment thresholds may still qualify for treatment based on vertebral fractures detected through VFA
By following these evidence-based recommendations for DEXA scanning, clinicians can effectively identify patients at risk for osteoporotic fractures and initiate appropriate interventions to reduce morbidity and mortality.