Advice

Clinical and technical evidence

Clinical and technical evidence

A literature search was done for this briefing in accordance with the interim process and methods statement. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology. Further information about how the evidence for this briefing was selected is available on request by contacting mibs@nice.org.uk.

Published evidence

Two studies including 1,127 people are summarised in this briefing. One study (Karjalainen et al. 2016) examined the association between dual‑energy X‑ray absorptiometry (DXA) measurements at the proximal femur and Bindex (measured at the tibia), using a diagnostic threshold for the density index based on International Society for Clinical Densitometry (ISCD) and National Osteoporosis Society guidelines. The study by Schousboe et al. (2017) estimated the diagnostic accuracy of Bindex using the threshold density index from the Karjalainen et al. (2016) study.

Table 2 summarises the clinical evidence as well as its strengths and limitations.

Overall assessment of the evidence

The evidence comes from 2 large diagnostic accuracy studies with participants recruited in the USA and Finland. No UK studies were found. The current evidence shows reasonable agreement for osteoporosis risk when determined using FRAX and Bindex compared with FRAX and DXA, which is a relevant outcome for the NHS. Both studies include authors affiliated to and in receipt of funding from the manufacturer.

The relationship of cortical thickness and density index may vary in populations of differing ethnicities. Therefore the density index thresholds need to be validated in a wider population (including women and men of differing ethnicities). Additional prospective validation studies to explore if using Bindex would decrease the number of DXA referrals and increase diagnosis using the thresholds defined by Karjalainen et al. (2016) would also be useful.

Table 2 Summary of evidence

Karjalainen et al. (2016)

Study size, design and location

572 women of white European family origin (aged 20 to 91 years). Diagnostic accuracy study, but it is unclear if the study was prospective or retrospective. Set in Finland.

Intervention and comparator(s)

Bindex compared with DXA; FRAX and Bindex compared with FRAX and DXA.

Key outcomes

The FRAX followed by Bindex approach showed 85% sensitivity and 79% specificity for treatment decisions based on the Finnish standard criteria, when compared with treatment decisions obtained by FRAX and DXA. The false negative rate of the FRAX followed by Bindex approach was 14.6%.

Using the FRAX followed by Bindex approach, 84% (of the total number of women) avoided DXA tests with the Bindex approach. Reproducibility between Bindex operators was good.

Strengths and limitations

The comparator was similar to UK standard care, so some of the study results may be generalisable to the NHS. However, the study did not take into account the use of DXA for baseline measurements to monitor treatment efficacy.

The same population was used to develop and validate the density index thresholds, so the results do not validate the performance of Bindex.

Schousboe et al. (2017)

Study size, design and location

555 post-menopausal women (43% with hip osteoporosis, 57% without hip osteoporosis), to investigate diagnostic accuracy (recruited by mail from the local bone densitometry database), based in the USA.

Intervention and comparator(s)

Bindex compared with DXA.

Key outcomes

Using single- or multi-site density index measures (taken from the proximal and distal tibia and radius) could decrease the number of follow‑up DXA by about 70% in post-menopausal women who were screened for hip osteoporosis. Multi-site and single-site density index measures were shown to have good sensitivity and specificity (80–82%).

Strengths and limitations

The study is from an American centre, so the results may not be generalisable to the NHS. Recruitment by mail has an effect on the participation of frail individuals with hip osteoporosis who could not travel to the clinic. The manufacturer states that measurements should be taken from the upper shaft of the tibia, but measurements were taken from other bones in this study.

Recent and ongoing studies

One ongoing trial was identified.