FRAX™ and the assessment of fracture probability in men and women from the UK

Abstract

Summary A fracture risk assessment tool (FRAX™) is developed based on the use of clinical risk factors with or without bone mineral density tests applied to the UK. Introduction The aim of this study was to apply an assessment tool for the prediction of fracture in men and women with the use of clinical risk factors (CRFs) for fracture with and without the use of femoral neck bone mineral density (BMD). The clinical risk factors, identified from previous meta-analyses, comprised body mass index (BMI, as a continuous variable), a prior history of fracture, a parental history of hip fracture, use of oral glucocorticoids, rheumatoid arthritis and other secondary causes of osteoporosis, current smoking, and alcohol intake 3 or more units daily. Methods Four models were constructed to compute fracture probabilities based on the epidemiology of fracture in the UK. The models comprised the ten-year probability of hip fracture, with and without femoral neck BMD, and the tenyear probability of a major osteoporotic fracture, with and without BMD. For each model fracture and death hazards were computed as continuous functions. Results Each clinical risk factor contributed to fracture probability. In the absence of BMD, hip fracture probability in women with a fixed BMI (25 kg/m 2 ) ranged from 0.2% at the age of 50 years for women without CRF's to 22% at the age of 80 years with a parental history of hip fracture (approximately 100-fold range). In men, the probabilities were lower, as was the range (0.1 to 11% in the examples above). For a major osteoporotic fracture the probabilities ranged from 3.5% to 31% in women, and from 2.8% to 15% in men in the example above. The presence of one or more risk factors increased probabilities in an incremental manner. The differences in probabilities between men and women were comparable at any given T-score and age, except in the elderly where probabilities were higher in women than in men due to the higher mortality of the latter. Conclusion The models provide a framework which enhances the assessment of fracture risk in both men and women by the integration of clinical risk factors alone and/ or in combination with BMD.

Subtrochanteric/femoral shaft Versus hip fractures: Incidences and identification of risk factors

“…(16) In our study, the higher frequency of dementia could be related to the exhaustive nature of the reports. Obesity is often found to be a protective factor against hip fracture; (28,29) however, excess subcutaneous fat with less lean mass may alter the gait, thus predisposing individuals to falls. Indeed, obesity modifies the mechanical impact at the hip, which may consequently be transmitted to the diaphysis, (30) where the adipose tissue may have less shock-absorbing effect than at the hip.…”

Towards new material biomarkers for fracture risk

“…Unfortunately DEXA is not without limitations and is arguably a poor predictor of fracture, with a study carried out by Wainwright et al showing that 54% of new hip fractures occurred in women who did not have osteoporosis as determined by their BMD [7] and data from the National Osteoporosis Risk Assessment, showed that 82% of post-menopausal women with fractures had bone of 'normal' BMD [8]. The limitation of DEXA was perhaps highlighted with the development of FRAX, the World Health Organisation (WHO) fracture assessment tool, which uses BMD along with clinical risk factors and country-specific fracture and mortality data to quantify a patient's 10-year probability of a hip or major osteoporotic fracture [9].…”

Fracture risk prediction using BMD and clinical risk factors in early postmenopausal women: Sensitivity of the WHO FRAX tool

“…In this regard, the WHO's fracture risk assessment tool (FRAX), which has just been launched during this last year, allows one to calculate the 10-year probability of fractures in men and women from several clinical risk factors (CRFs) with or without the measurement of femoral neck BMD. (6,7) The performance characteristics of the FRAX tool have been validated in independent cohorts with over 1 million person-years of observation. However, most, if not all, of these cohorts concern elderly women, usually over the age of 65 and have focused mainly on hip fractures.…”