Assessing Your Fracture Risk: Beyond Bone Density

When you are taking steroids long-term, a standard bone density scan is only one piece of a much larger puzzle. Because Glucocorticoid-Induced Osteoporosis (GIOP) damages the microarchitecture (the internal honeycomb-like structure) of your bones faster than it reduces their density, your risk of a fracture is often much higher than a simple scan might suggest ^[1][2].

To accurately assess your risk, current guidelines from the American College of Rheumatology (ACR) recommend a comprehensive clinical fracture-risk assessment that combines a review of your medical history, bone density imaging, and an adjusted risk calculator ^[3].

1. The DXA Scan: Density vs. Quality

The Dual-Energy X-ray Absorptiometry (DXA) scan measures your Bone Mineral Density (BMD)—essentially how much “mineral” is packed into your bone ^[3]. The results are usually given as two different scores:

• T-score: Used for postmenopausal women and men aged 50 years or older. This compares your bone density to that of a healthy young adult. A T-score of -2.5 or lower is the densitometric definition of osteoporosis ^[4].
• Z-score: Used for premenopausal women and men younger than 50. This compares your density to people of your same age, sex, and ethnicity. A Z-score of -2.0 or lower means the bone density is “below the expected range for age” ^[4]. It is not an automatic diagnosis of urgent osteoporosis, but it requires careful clinical context to make treatment decisions.

The GIOP Gap: Steroids can make bone more “brittle” without immediately making it “thinner” on a DXA scan. You may have a “non-osteoporotic” T-score but still be at high risk for a fracture ^[5]. This is why relying on a DXA scan alone is often insufficient for patients on steroids ^[1].

2. FRAX: Calculating Your Probability

FRAX is a probability calculator that estimates your 10-year probability of suffering a major osteoporotic fracture or a hip fracture ^[6]. It is primarily validated for adults aged 40 to 90. It looks at your age, weight, prior fractures, parental hip fracture, rheumatoid arthritis, smoking, alcohol use, and steroid use ^[7].

Crucially, the standard FRAX tool only has a “yes/no” box for steroids, which assumes an average, medium-dose exposure. Because risk increases with the dose, your doctor must manually correct the FRAX result to account for your specific exposure ^[3][7]. If you are on a high dose, an unadjusted FRAX score will underestimate your true risk; if you are on a very low dose, it may overestimate it ^[8].

3. VFA and TBS: Looking Inside the Bone

Because spinal fractures in GIOP are often “silent” (occurring without pain), the 2022 ACR guidelines recommend Vertebral Fracture Assessment (VFA) or a spinal X-ray depending on your age, clinical risk, prior fracture, height loss, and symptoms ^[3].

• VFA: This is a low-dose X-ray, often taken at the same time as your DXA, specifically designed to look for existing collapses in the vertebrae ^[9].
• Trabecular Bone Score (TBS): This is an optional software adjunct that can be applied to your DXA images. It evaluates the texture and structure of the bone rather than just the density ^[10]. While not mandatory, a low TBS score indicates that the internal “honeycomb” structure of the bone is degraded, which is common in steroid users even when their BMD density appears normal ^[1][11].

Completeness Checklist

You can use this checklist to review your most recent bone health report. If any of these are missing, it is a good starting point for a conversation with your healthcare team.

• [ ] Bone Mineral Density (BMD): Does the report include your T-scores (for adults over 50) or Z-scores (for younger adults)? ^[3]
• [ ] Adjusted FRAX Score (if 40+): Was your FRAX score calculated, and did the doctor apply a correction for your specific steroid dose? ^[3][7]
• [ ] Vertebral Imaging: Have you had a VFA or a lateral spinal X-ray to check for silent fractures based on your clinical risk? ^[3]
• [ ] Risk Categorization: Based on these results, has your doctor clearly stated if you are in the “Low,” “Moderate,” “High,” or “Very High” risk category? ^[3]
• [ ] Baseline Measurement: If you just started steroids, was this assessment done as soon as possible (generally within the first 6 months) to establish your baseline? ^[3]