More About the FORE Fracture Risk Calculator (FRC) and the WHO FRAX
Because the FORE FRC does not build in the same "mortality offset" found in FRAX, FRC will yield higher rates of fracture in women with conditions associated with shorter life expectancy (e.g. age over 80 years, very low BMD, very low BMI, etc.) Our assumption is that doctors who calculate fracture risk from BMD and who are considering osteoporosis drug therapies assume at least a 10 year life expectancy.
The cost effectiveness study (Tosteson ANA, et al. Osteoporos Int 2008; 19:437-47) was based on Rochester MN population fracture rates and used the WHO model for fracture risks. The primary outcome studied was hip fracture with a secondary outcome as any one of four fractures (vertebra, femur, wrist, or humerus). The researchers looked at a 10-year window and assumed a 35% risk reduction from treatment. Based on those assumptions, the authors determined that HIGH RISK was defined as a 3% chance of hip fracture in the next 10 years or a 20% chance of any of four other fractures.
Based on the cost effectiveness study, the National Osteoporosis Foundation has published treatment guidelines summarized below.
Consider pharmacological therapies based on:
- A vertebral or hip fracture
- A hip or spine T-score below -2.5
- Low bone mineral density (BMD) and a FRAX 10-year risk at least 3% for hip or 20% of any of 4-fractures.
- Patient's preferences
Bruce Ettinger, MD has published an extensive description of the FRC and FRAX models and their use in clinical practice in the journal Menopause (download PDF, 1.0 MB).