For a nonagenarian (someone in their 90s), the decision to pursue a bone density test, or DEXA scan, is far more nuanced than for a younger, healthier adult. While advanced age is a significant risk factor for bone loss, the clinical value of a diagnosis must be considered in the context of the individual's specific health profile, goals of care, and overall prognosis. This advanced age group is not as well-represented in clinical studies, meaning guidelines are less definitive. A detailed discussion with a geriatric specialist is crucial to determine if the test and potential treatment align with the patient's priorities.
The Role of Testing in Nonagenarians
Bone mineral density (BMD) testing in a 90-year-old is not performed for routine screening but rather to guide treatment decisions. The key question is whether the results of the test would lead to a change in the patient's management plan. For some, identifying osteoporosis may justify starting or adjusting medication to prevent a debilitating fracture, like a hip fracture, that could severely impact their quality of life and independence. For others, especially those with multiple other health conditions, limited mobility, or a short life expectancy, the potential benefits of treatment may not outweigh the burdens and side effects of medication.
Factors Influencing the Decision
- Individual's Care Priorities: The patient's and their family's goals are paramount. Do they prioritize comfort and minimizing medication, or is preserving independent mobility worth pursuing aggressive treatment?
- Presence of Fragility Fractures: If a 90-year-old has already experienced a low-impact fracture (e.g., from a standing-height fall), they are automatically considered to have osteoporosis, regardless of their BMD score. In this case, a DEXA scan is not necessary for diagnosis, but may be used to monitor treatment.
- Overall Health and Frailty: A person's frailty level and the presence of other medical conditions (comorbidities) are significant considerations. The benefits of long-term osteoporosis medication are less relevant for someone with a limited prognosis.
- Fall Risk Assessment: For the very elderly, preventing falls is often a more impactful strategy for fracture prevention than just increasing bone density. Medications and physical therapy to improve balance and strength can be considered independently of a DEXA result.
What a DEXA Scan Can Reveal
A DEXA scan for a 90-year-old can provide valuable information in specific scenarios. The T-score, which compares the patient's bone density to that of a healthy young adult, can diagnose osteoporosis or osteopenia. However, the Z-score, which compares the patient's bone density to their age-matched peers, is often more relevant in the very elderly to identify whether bone loss is significantly accelerated compared to their peers. The test also assesses fracture probability over 10 years, using tools like FRAX, which incorporates other risk factors alongside the DEXA results.
Weighing Benefits and Risks
Comparison of Benefits vs. Risks for a 90-Year-Old
| Feature | Benefits of a Bone Density Test | Risks and Considerations |
|---|---|---|
| Informing Treatment | Can confirm severe osteoporosis, justifying the use of medications to significantly reduce fracture risk, especially for a mobile, independent person. | Treatment decisions are not based on the test alone; it must be coupled with an assessment of the individual's overall health and frailty. |
| Preventing Fractures | Identifies weakened bones, allowing for proactive intervention with medication and fall prevention to avoid a devastating fracture. | For many nonagenarians, fall prevention is more critical and can be managed without a DEXA. The time-to-benefit for osteoporosis medication may exceed the patient's life expectancy. |
| Radiation Exposure | The amount of radiation is minimal, less than a chest X-ray and well below natural background radiation. | While minimal, any added radiation exposure should be weighed against the potential benefits, especially if the result is unlikely to change the care plan. |
| Convenience and Burden | The scan is quick (10-15 minutes), painless, and non-invasive. | The scan and follow-up can add to the burden of medical appointments, which can be taxing for the very elderly. |
| Cost | Medicare often covers DEXA scans for individuals over 65 or 70, potentially every two years. | Potential out-of-pocket costs, and the overall cost to the healthcare system, should be considered if the clinical utility is low. |
Alternatives to a DEXA Scan in Advanced Age
In some cases, a DEXA scan may not be the most appropriate or necessary diagnostic tool for a 90-year-old. Alternatives and complementary strategies include:
- Clinical Risk Factor Assessment: Using tools like FRAX (without the BMD input) to estimate fracture risk based on other factors like personal and family history of fractures, use of certain medications, and smoking history.
- Fall Risk Evaluation: A comprehensive evaluation of the home environment, medication review, and balance assessment can help prevent fractures by addressing the most common cause in the elderly: falls.
- Vertebral Imaging: If there is suspicion of a spinal fracture, a vertebral imaging study may be more direct and useful, particularly if the T-score is already low.
- Treatment without Testing: For individuals with multiple high-risk factors or a prior fragility fracture, a clinician may recommend starting treatment directly without a DEXA, as the diagnosis is already clinically certain.
Conclusion: Making a Personalized Choice
The necessity of a bone density test for a 90-year-old is a decision to be made on an individual basis, in close consultation with a healthcare provider, ideally a geriatric specialist. While advanced age puts individuals at high risk for osteoporosis, the relevance of a DEXA scan hinges on whether the results will meaningfully alter the patient's care plan. The primary consideration should be the patient's overall health, life expectancy, and personal goals. For an active, independent nonagenarian, a DEXA could be a valuable tool to prevent a life-altering fracture. However, for a frail, less mobile individual, focusing on falls prevention and minimizing medical burden may be a more appropriate course of action. Ultimately, there is no upper age limit for screening, but the decision must be clinically driven by the potential for actionable, beneficial intervention.
Mayo Clinic News Network provides further insights into who should get a bone density test based on age and risk factors.
