Version 2.0 - December 2012
As new information about fracture risk is published, we are updating the FORE Fracture Risk Calculator (FRC). Several new published articles have allowed us to make four modifications to the calculator to improve its predictive performance. These are as follows:
Inclusion of vertebral fracture as a separate risk factor.
Black et al 1 have estimated how much the presence of a baseline vertebral fracture contributes independently to risks of both future hip and major osteoporotic fractures. 1 These risks are beyond those imposed by history of other low trauma fractures and should be considered as a separate input risk variable. Any clinically apparent spine fracture (i.e. back pain plus radiographic conformation) would qualify. However, when a vertebral deformity is found on a radiograph only (i.e. morphometry), only a severe degree (>30% vertebral height loss) vertebral deformity would qualify.
Inclusion of spine bone mineral density (BMD) together with the usual femoral neck BMD.
Leslie et al 2 have assessed the contribution of spine BMD to the FRAX™ 10-year fracture calculation and concluded that spine BMD adds a small modifying effect once femoral neck BMD is entered. Leslie found that the best use of BMD as a predictor of future fracture was to use BOTH (not the lower of the two); further best results were obtained when femoral neck BMD T-score was weighted 3 times as much as spine BMD. Since FRAX™ and FRC yield similar results when tested in the same populations 3-6, we have applied the Leslie et al weighting equation in FRC. The input list now includes a space for spine T-score as well as femoral neck T-score.
Consideration of the dose of oral glucocorticoid.
Kanis et al 7 examined the contribution of glucocorticoid dose on FRAX™ fracture risk and concluded that risk of fracture in people using daily doses in excess of 7.5mg prednisolone is approximately 21% higher than those using 5-7.5 mg doses. On the FRC input variable page, we now offer choices of glucocorticoid dosage.
Use of a more accurate calculation of risk related to BMD in men.
The FORE FRC calculator uses BMD Z-score (not T-score) as the risk modifying variable. Based on the standard NHANES III reference ranges for women of various ages, we previously included conversions from femoral neck T-score (input variable) to femoral neck Z-score (calculation variable). Now with the addition of spine BMD T-scores and a similar need to convert them to Z-scores, we recognized the need to have both machine-specific and gender-specific conversion values. Thus, when entering spine T-score, users must also enter the machine type--- either Hologic or GE/Lunar.
Explanations for each of these changes and supporting references can be obtained by clicking on the link(s) above.
- Black DM, Arden NK, Palermo L, Person J, Cummings SR. Prevalent vertebral deformities predict hip fractures and new vertebral fractures but not wrist fractures. Study of Osteoporotic Fractures Research Group. J Bone Miner Res 14:821-828,1999.
- Leslie WD, Lix LM, Johansson H, et al. A comparative study of using non-hip bone density inputs with FRAX. Osteoporos Int 23:853-860, 2012
- Lo JC, Pressman AR, Chandra M, Ettinger B. Fracture risk tool validation in an integrated healthcare delivery system. Am J Manag Care 17:188-194, 2011.
- Pressman AR, Lo JC, Chandra M, Ettinger B. Methods for assessing fracture risk prediction models: Experience with FRAX in a large integrated healthcare delivery system. J Clin Densitometry 14:407-415, 2011.
- Ettinger B, Liu H, Blackwell T, et al. Validation of FRC, a fracture risk assessment tool, in a cohort of older men: The Osteoporotic Fractures in Men Study. J Clin Densitometry 2012.
- Ettinger B, Ensrud K, Blackwell K, et al. Performance of FRAX in a cohort of ambulatory, community-dwelling, older men: The Osteoporotic Fractures in Men (MrOS) Study. (Submitted May 2012).
- Kanis JA, Johansson H, Oden A, McCloskey EV. Guidance for the adjustment of FRAX according to the dose of glucocorticoids. Osteoporos Int 22:809-816, 2011.