Notes

Background:

The predicted hip fracture rates are derived from the patient's age, the Clinical Risk Factor information supplied above, and the measured hip bone density. The calculations are based on data from untreated postmenopausal Caucasian females and should not be extrapolated to other groups. The fracture estimates are for information only and do not replace the clinical judgement of a qualified medical professional.

Number of years Needed to Treat (NNT):

A way of presenting the effects of treatment for cost-effectiveness analyses and guiding public health programmes towards the identification of optimal treatment strategies. NNT is calculated as the reciprocal of a treatment's yearly absolute risk reduction. The NNT does not apply when hip BMD is not in the osteoporotic range (T-Score less than -2.5).

Assumptions:

That the various fracture predictors operate independently, that hip fracture rates increases 2.6 times for each unit decrease in hip T-score, and that therapy leads to a 50% relative risk reduction in hip fractures when hip BMD is in the osteoporotic range (T-Score less than -2.5).

References:

• Risk factors for hip fracture in white women (NEJM 1995;332:767).
• Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures (BMJ 1996;312:1254-1259).
• The role of clinical risk factors in the prediction of future fracture risk (J Clinical Densitometry 1999;2:361-362).
• Risk of hip fracture derived from relative risks: an analysis applied to the population of Sweden (Osteoporosis Int 2000;11:120-127).
• Bone mineral density testing in healthy postmenopausal women: the role of clinical risk factor assessment (J Clinical Densitometry, in press).