Calibration of FRAX : A journey, not a destination [Editorial]

[Extract] The management of osteoporosis has been revolutionized by the shift, in part or in whole, from treatment of individuals with low bone mineral density (BMD) T-scores to those with elevated absolute fracture risk based upon clinical prediction tools. Among the available validated tools, FRAXR is unique in several respects including its ability to customize predictions to a specific target population [1]. This process, known as calibration, ensures that the output from FRAX—10-year probability of major osteoporotic fracture (MOF, a composite of hip, clinical vertebral, proximal humerus, distal forearm) and 10-year probability of hip fracture alone—agrees with the expected fracture risk. This has allowed for the creation of more than 80 FRAX tools covering over 80% percent of the world population. [2] The flexibility of this approach, which recognizes diversity in fracture risk between populations rather than making the flawed assumption that “one size fits all”, comes at a price. That price is the need to acquire high quality fracture incidence rates. (Mortality data are also required to incorporate competing mortality into the calculation but are usually easier to obtain.).