Calibration of FRAX: A Journey, not a Destination

Excerpt

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, FRAX^R 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.). …