FRAX® WHO Fracture Risk Assessment Tool 

FRAX® is an osteoporosis risk assessment tool developed for the World Health Organization (WHO) to enhance the determination of fracture risk (and candidates for therapy) globally. The FRAX® system is a computer-based algorithm incorporating clinical risk factors with femoral neck bone mineral density to determine a 10-year absolute risk of fracture (hip and spine/humerus/wrist/hip). The FRAX® risk assessment tool is the product of a mega-analysis of many international observational databases (including Camos in Canada) relating risk factors to eventual fracture. Details of the risk assessment tool are available at FRAX®–WHO Fracture Risk Assessment Tool.

It is important that FRAX® be calibrated to the country hip fracture and survival data. This has been done for a number of countries including Canada. Canada is not yet an option on the FRAX® website because Osteoporosis Canada prohibits access to this model for Canadians. We hope this will soon change. In the meantime, it is best advised to use the U.S. FRAX® models, as they are very close to what the Canadian models would be.

The Canadian Association of Radiology has promoted a 10-year absolute fracture risk assessment model based on Swedish data and offering "bands" of risk (low, moderate, high). This has limited utility for the Canadian population but may be used as a bridge to the more sophisticated FRAX® model. In addition, in the absence of treatment guidelines, treatment of patients at "moderate risk" remains as problematic as determining treatment for patients with "osteopenia."

Subsequent to the adoption of an absolute fracture risk system, it is important that evidence-based treatment thresholds be determined and implemented. In the absence of an Osteoporosis Canada guideline, it is best to adopt the U.S. National Osteoporosis Foundation guideline for therapy as stated below:

Postmenopausal women and men over age 50:

  • A hip or vertebral (clinical or morphometric) fracture

  • T-score ≤ -2.5 after excluding secondary causes

  • Low bone mass (-1 to -2.5) and

  • Other prior fractures, or

  • Secondary causes (such as glucocorticoid use or total immobilization), or

  • 10-year probability of hip fracture ≥ 3% or a 10-year probability of any major osteoporosis-related fracture ≥ 20% based on the U.S.-adapted WHO algorithm

These guidelines do not substitute for good clinical judgment and are not meant to restrict therapy. They are meant to direct therapy to those patients most deserving based on clinical risks, densitometric parameters and a 10-year absolute fracture risk assessment.

  

 

Copyright © 2008-2010 Dr. David Kendler

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