Posts Tagged ‘DXA’
Treat to Target of NO NEW FRACTURES. How do we find that target? DXA >-2.5 is a start. Fragility fractures increase new fracture risk. FRAX adds many more risk factors to the calculation and TBS refines FRAX.
Vertebral Fracture Assessment (VFA) looks at the spine from the side and independently identifies additional fracture risk. This can be done on a DXA machine or by x-ray. A single vertebral compression fracture of 25% or more pre-empts DXA, BMD, and FRAX in diagnosing Clinical Osteoporosis and recommending treatment.
VFA should be done because the majority of vertebral compression fractures are first noticed by x-ray or DXA VFA imaging. If you do not personally view the images, be sure the radiologist specifically checked for vertebral deformities as described by Genant.
I recently published my retrospective review of 1259 sequential first time VFA patients in Endocrine Practice 2017:23:1375-8.
VFA identified many patients not identified as high fracture risk (Clinical Osteoporosis) by DXA or fragility fracture or height loss or kyphosis or FRAX.
We should consider including VFA in every first time Complete Bone Health Evaluation.
And how should we treat? Next time…
Jay Ginther, MD
Our goal is NO NEW FRACTURES. Cancellous (spongy, like the ends of the drumstick) bone should be a strong latticework of struts called trabeculi. Clinical Osteoporosis, an increased fracture risk, occurs when some of the struts disappear.
Trabecular Bone Score (TBS) evaluates the spongy bone in the DXA images of the vertebrae (spine) looking for irregularities. When TBS finds uneven bone mineral density within the spine DXA, that indicates a higher fracture risk, regardless of the total BMD.
Adding the TBS feature to a DXA machine allows the quality of bone in the spine to influence the FRAX score, just like the BMD in the femoral neck part of the hip influences the FRAX score. Adding TBS detects more patients at high fracture risk who should be treated to avoid fractures.
Diabetes increases a person’s fracture risk for any given DXA BMD or T-score. Controlled diabetes adds about the same risk as rheumatoid arthritis, so we usually check that box in FRAX. Uncontrolled diabetes is more serious requiring further adjustment to FRAX.
FRAX is pre-empted by a hip fracture. “Do not pass GO, do not collect $200, start a pharmaceutical” Vertebral (spine) Fracture is the same, but the majority of spine fractures are not noticed clinically. “Morphometric” (first noticed on x-ray) vertebral fractures count, but how to find them?
VFA next time
Jay Ginther, MD
Our Target is NO NEW FRACTURES. The original goal by DXA was a T-score of -2.4 or better. But age is a huge factor in actual fracture risk. The fracture risk of a T-score of -2.5 at age 60 is the same as a T-score of -3.1 at age 50, is the same as a T-score of -1.3 at age 80.
FRAX was developed by WHO and the International Osteoporosis Foundation to take age and other factors into account. The big 5 risk factors are age, previous fracture, parental hip fracture, smoking, and oral or inhaled corticosteroids. Rheumatoid arthritis (or diabetes), over 3 doses of alcohol daily, and BMI < 19 or > 35 also count. Male and Female are different. Femoral Neck of the hip BMD by DXA is only 30% of the calculation when available.
Treat to Target by FRAX is a “Major Osteoporotic” (wrist, shoulder, hip or clinically noticed spine) Fracture Risk of < 20%. Alternately a Hip Fracture Risk of < 3.0 is the target. FRAX identifies a more individualized fracture risk than DXA with or without fragility fracture.
Look up the FRAX tool at http://www.sheffield.ac.uk/FRAX/
FRAX gives different targets than DXA because it takes additional risk factors into account. And there have been some refinements added.
Jay Ginther, MD
Treat to Target means aiming for NO NEW FRACTURES. As discussed last time, the original target was to maintain Bone Mineral Density (BMD) at the level first tested. 25 years ago that was amended to be a T-score of -2.4 or higher, since “osteoporosis the test result” was set at -2.5.
But what if you already have fractured? Clinical Osteoporosis the diagnosis is a T-score of -1.5 plus a “Fragility Fracture” acquired in any fall from standing height, even on ice. That is because for the first year after a fracture your risk is 5 times normal. Your risk decreases to 2 times normal after 5 years, but always is higher after a fragility fracture.
If your Fragility Fracture was a Hip Fracture, you have Clinical Osteoporosis regardless of DXA BMD and T-score. You are at high risk of future fracture, especially of the other hip. You should start treatment to prevent a new fracture. At the very least you need to optimize calcium, vitamin D3, protein, and multiple vitamins & minerals intake.
If you also need a pharmaceutical, it should be one which can raise your T-score above -2.5 if you have no fractures, and above -1.5 if you already have a fracture. That usually means considering an anabolic. Your goal is NO NEW FRACTURES.
FRAX next time.
Jay Ginther, MD