May 01, 2020

Do Traumatic Fractures Relate to Osteoporosis? Is a Paradigm Shift Coming?

Posted By: Richard S. Pope, PA-C, MPAS

A new study by Leslie and colleagues evaluating high and low trauma fractures may change our thought process regarding how traumatic fractures pertain to risk for future fracture in patients with osteoporosis. The authors of this registry study—using data from Manitoba, Canada over a twenty-year period—hypothesized that high trauma fracture would not predict an increased risk of fracture, but that low trauma fracture would. Surprisingly, the study showed higher risk for both groups as compared to those without fracture. Data from 64,428 women and men over the age of 40 were retrospectively reviewed, correlating mean bone mineral density (BMD) Z-scores with high and low trauma fractures. The study was published in Osteoporosis International in December 2019.

The term "fragility fracture" has been associated with osteoporosis for many years. A fragility fracture has been described as a fall from a standing height or less that results in a fracture that would not otherwise occur in a healthy individual. The Fracture Risk Assessment (FRAX) calculator describes how to answer the question on "previous fracture" this way: "A previous fracture denotes more accurately a previous fracture in adult life occurring spontaneously, or a fracture arising from trauma which, in a healthy individual, would not have resulted in a fracture." This description omits the notion of trauma (which includes external forces such as speed, height, angle, objects, etc) and opens the door for the practitioner to interpret it.

In clinical practice, we spend time trying to identify the specific traumatic mechanism(s) that may have led to a prior fracture. This is important, as we believe that a fracture—if it was due to fragility—would be the key to answering this question correctly. The statement "in a healthy individual would not have resulted in a fracture" is exactly the question this study is trying to answer.

In the study by Leslie and colleagues, BMD Z-scores for those with any prior high trauma fracture were significantly lower than for those without prior fracture. Similar results were found with the low trauma fracture group when compared to those who did not have fracture. Trauma was captured in the Canadian registry using E codes from ICD-9-CM and X, V, and W codes from the ICD-10-CA hospital-based coding used in Canada. The statistical analysis used the index date as the DXA scan date, and the primary outcome was incident fractures occurring after the index date. The median observation time was 8.8 years, with total observation time for incident fractures of 729,069 person years, and extended from January 1996 to March 2016.

The findings from this study support a more inclusive approach as to how to answer the question "previous fracture?" This study, along with others that showed similar results (SOF 2007, MrOS 2007 research groups, Geelong Osteoporosis Study 1998), will likely be used in routine clinical practice in the future to simplify the answer to the question "previous fracture" on the FRAX calculator. I look forward to in-depth evaluations of trauma and how these data will be interpreted by national guideline groups.

References

Leslie WD, Schousboe JT, Morin SN, et al. Fracture risk following high-trauma versus low-trauma fracture: a registry-based cohort study. Osteoporosis Int. 2020; [epub ahead of print].
University of Sheffield. FRAX Fracture Risk Assessment Tool. www.sheffield.ac.uk/FRAX/tool.aspx?country=9. Accessed April 30, 2020.

Filed under: Orthopedics , Rheumatology