ARS | Publication request: Updated fracture incidence rates for the US version of FRAX (registered trademark)

Submitted to: Osteoporosis International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 26, 2009
Publication Date: January 1, 2010
Citation: Ettinger, B., Black, D., Dawson-Hughes, B., Pressman, A.R., Melton, L. 2010. Updated fracture incidence rates for the US version of FRAX (registered trademark). Osteoporosis International. 21:25-33.

Interpretive Summary: The World Health Organization (WHO) has developed a formula for calculating 10-year fracture probability that takes into account an individual’s bone mineral density and clinical risk factors. The tool is adapted to specific countries, a process that involves inclusion of nation-specific fracture rates and mortality rates into the formula. This calculator, known as FRAX (trademarked), is being used in combination with National Osteoporosis Foundation Guidelines by clinicians to determine who among U.S. postmenopausal women and men age 50 years and older should be considered for treatment to prevent fractures. Since FRAX was initially adapted for use in the U.S., fracture rates and mortality rates here have declined. These declines affect the fracture risk values derived from FRAX. In order to recalibrate FRAX for the U.S., we conducted this analysis to derive more accurate fracture rate estimates for men and women of different ethnicities, with use of a variety of data sources. The data provided will be used by the WHO to update the US version of FRAX. Both clinicians and the general older population stand to benefit from more accurate estimates of fracture risk.

Technical Abstract: Evaluation of results produced by the US version of FRAX (trademarked) indicates that this tool overestimates the likelihood of major osteoporotic fracture. In an attempt to correct this, we updated underlying baseline fracture rates for the model. We used US hospital discharge data from 2006 to calculate annual age- and sex-specific hip fracture rates, and age-specific ratios to estimate clinical vertebral fracture rates. To estimate the probability of any one of four major osteoporotic fractures, we first summed these newly derived hip and vertebral fracture estimates with Olmsted County, MN, wrist and upper humerus fracture rates, and then applied a 10-20% discount for overlap. Compared with rates used in the current FRAX (trademarked) tool, 2006 hip fracture rates are about 16% lower, with greatest reductions observed among those <age 65 years; major osteoporotic fracture rates are about one-third lower, with similar reductions across all ages. We recommend revising the US-FRAX by updating current base population values for hip fracture and major osteoporotic fracture. The impact of these revisions on FRAX (trademarked) is likely to be lowering of 10-year fracture results. More precise estimates of the impact of these changes on 10-year fracture probabilities will be available after these new rates are incorporated into the FRAX (trademarked) tool.