What is the next recommended diagnostic test for a 71-year-old patient with vertebral compression fractures on alendronate (bisphosphonate) and ibuprofen (Non-Steroidal Anti-Inflammatory Drug (NSAID))?

Next Diagnostic Test for a 71-Year-Old with Vertebral Compression Fracture on Alendronate

For a 71-year-old patient with vertebral compression fractures on alendronate and ibuprofen, a bone mineral density (BMD) test using dual-energy x-ray absorptiometry (DXA) of the lumbar spine and hip is the recommended next diagnostic test.

Rationale for DXA Testing

The patient presents with several important clinical factors that guide this recommendation:

1. Established vertebral compression fracture: This indicates possible osteoporosis
2. Age 71 years: Advanced age is a significant risk factor for osteoporosis
3. History of polymyalgia rheumatica: This condition often requires corticosteroid treatment, which increases osteoporosis risk
4. Already started on alendronate: Baseline BMD measurement is essential for monitoring treatment effectiveness

Evidence Supporting DXA Testing

According to the American College of Radiology (ACR) Appropriateness Criteria, DXA of the lumbar spine and hip is rated as "usually appropriate" (rating of 7 out of 9) for patients with suspected osteoporosis 1. This test provides:

• Quantitative measurement of bone density
• Baseline values to monitor treatment response
• T-scores to assess fracture risk
• Low radiation exposure compared to other imaging modalities

Monitoring Recommendations

The National Comprehensive Cancer Network (NCCN) guidelines, which address bone health in various conditions, recommend:

• A baseline DXA scan before starting therapy in patients at increased risk for fracture 1
• Follow-up DXA scan after 1 year of therapy as recommended by the International Society for Clinical Densitometry 1

Praxis Medical Insights further specifies that:

• For patients with normal BMD, DEXA should be repeated after 2-3 years
• For those with rapid bone loss risk, DEXA should be repeated within 1 year 2

Additional Testing Considerations

Vitamin D Testing

• Checking serum 25-hydroxy vitamin D levels is recommended alongside BMD testing 1
• This helps guide appropriate vitamin D supplementation, which is essential for bone health and optimizing bisphosphonate effectiveness

Fracture Risk Assessment

• FRAX algorithm calculation should be performed to assess 10-year probability of major osteoporotic fracture and hip fracture 1
• The patient's polymyalgia rheumatica (if treated with corticosteroids) should be considered as "secondary osteoporosis" when using the FRAX algorithm 1

Special Considerations for This Patient

Monitoring for Bisphosphonate Side Effects

Since the patient is already on alendronate, monitoring for potential complications is important:

• For patients on long-term bisphosphonate treatment (3-5 years) who develop thigh or groin pain, radiographs of the femur are recommended (rating of 9 out of 9) to assess for atypical femoral fractures 1
• If radiographs are negative but symptoms persist, MRI of the thigh without IV contrast is recommended (rating of 9 out of 9) 1

Polymyalgia Rheumatica Considerations

• If the patient has been treated with corticosteroids for polymyalgia rheumatica, this increases osteoporosis risk
• The NCCN guidelines specifically note that "ADT should be considered 'secondary osteoporosis' when using the FRAX algorithm" - this principle applies to corticosteroid use as well 1

Conclusion

DXA scanning of the lumbar spine and hip is the most appropriate next diagnostic test for this patient with vertebral compression fracture on alendronate. This will establish a baseline for monitoring treatment effectiveness and guide further management decisions.