Bone mineral density analyses using dual energy x-ray absorptiometry (DXA) for women in their 50th year

Kessels S, Schubert C, Parsons J, Morona J, Merlin T
Record ID 32015000100
Original Title: Application 1162
Authors' objectives: This proposal is for the provision of an MBS item number for bone mineral density (BMD) testing using dual energy x-ray absorptiometry (DXA) for all women in their 50th year with a view to identifying individuals with a low or low-normal BMD (that is individuals with a negative T-score) who may be at future increased fracture risk and who would be given appropriate dietary and lifestyle healthy bone advice. DXA scanning is considered the gold standard for the purposes of identifying patients with low BMD, predominantly due to cost-effectiveness and accessibility. It documents small changes in bone mass and can also be used to examine both the spine and the extremities.
Authors' results and conclusions: Safety - Due to lack of evidence on women in their 50th year alone, the inclusion criteria were broadened to capture all women in the perimenopausal period (i.e. women aged 40-65 years). No studies were identified that assessed the safety of DXA in women in this age bracket, but DXA is considered safe as radiation doses are smaller than most diagnostic X-ray examinations (e.g. X-ray mammography). Effectiveness - Studies meeting the pre-specified inclusion criteria and assessing the direct health impact of DXA versus no risk assessment in women aged 40–65 years were not available. In a study of postmenopausal women no significant change in BMD was reported; thus, the expected age-related reduction in BMD between visits was not found in the 12–18 months subsequent to DXA testing plus lifestyle counselling. In the second study (premenopausal women) there was a mean 1.1% per year increase in femoral neck BMD from baseline to 2 years, and no change in lumbar spine BMD when DXA testing was used in combination with lifestyle counselling. The study found that DXA plus informing women of the BMD results was effective at increasing hip BMD in the short term (2 years). The linked evidence analysis considered the accuracy of DXA compared with FRAX®, as reported in two studies. Both studies had a high loss to follow-up of participants (potential for selection bias). Also, the study participants were Asian women in the right age group, so the results may not be wholly applicable to an Australian population. The area under the curve (AUC) calculated for each of the studies showed average performance of both DXA and FRAX® in predicting fracture. DXA AUC values were 0.71 (95%CI 0.66, 0.76) and 0.64 (95%CI 0.57, 0.72) when predicting any major minimal trauma fracture, and 0.86 (95%CI 0.79, 0.92) and 0.82 (95%CI 0.67, 0.98) when predicting hip fracture, respectively. The predictive accuracy of FRAX® was very similar, with AUC values of 0.71 (95%CI 0.66, 0.76) and 0.67 (95%CI 0.59, 0.75) for any major fracture, and 0.90 (95%CI 0.83, 0.97) and 0.86 (95%CI 0.68, 1.00) for hip fracture, respectively. It would therefore appear that DXA is as accurate as clinical risk assessment (using FRAX® without DXA results). There was inadequate evidence available to determine the safety and effectiveness of BMD screening with DXA. Given the important impact of age on bone loss in women, it is difficult to determine whether the results described above would be replicated in women in their 50th year, and it is unclear how the BMD results could be extrapolated to predict fracture risk in an economic model without information on the individual osteoporotic risk factors present in Australian women aged 49 or 50 years. Further, as test accuracy was similar between DXA and clinical assessment, it is likely that similar impacts on health outcomes would be obtained using both methods, but that using a clinical assessment tool such as FRAX® would be less costly and without additional risk. Therefore, an evidence-based assessment of the cost-effectiveness of DXA for analysing BMD in women in their 50th year was not undertaken, as the resulting incremental cost-effectiveness ratio would be subject to an unacceptable level of uncertainty. Were the proposed listing to be implemented, after achieving a stable uptake over 4 years it might be expected to cost the MBS approximately $9.5 million per year (increasing annually). As the uptake is highly uncertain and depends on the extent of promotion of BMD screening using DXA, the financial impact may be in the range $2.5–$20 million.
Project Status: Completed
Year Published: 2014
English language abstract: An English language summary is available
Publication Type: Not Assigned
Country: Australia
MeSH Terms
  • Absorptiometry, Photon
  • Bone Density
  • Osteoporosis
  • Reference Values
  • Risk Assessment
  • Mass Screening
  • Middle Aged
  • Osteoporotic Fractures
Organisation Name: Adelaide Health Technology Assessment
Contact Address: School of Public Health, Mail Drop 545, University of Adelaide, Adelaide SA 5005, AUSTRALIA, Tel: +61 8 8313 4617
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Copyright: Adelaide Health Technology Assessment (AHTA)
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