DM PAD study 1.1
Research type
Research Study
Full title
Diagnostic tools to establish the presence and severity of peripheral arterial disease in people with diabetes
IRAS ID
301408
Contact name
Usman Jaffer
Contact email
Sponsor organisation
Joint Research Compliance Office, Imperial College London
Duration of Study in the UK
1 years, 11 months, 31 days
Research summary
THE PROBLEM
In the UK there are over 7,000 leg amputations each year because of diabetes. The most important cause of this is poor circulation. The detection of poor circulation in patients with diabetes is difficult. A number of tests exist to detect poor circulation. However, there is confusion as to which is the best test. We propose to carry out a study to determine which test is best.THE STUDY
We will ask adult patients with diabetes to take part in the study. The study will take place in 18 UK centres will be invited. Patients will be asked to attend two study visits. At the first visit, which will take 40 minutes and coincide with a routine appointment, patients will undergo five tests:•Blood pressure at the ankle (called ankle-brachial pressure index or ABPI)
•Blood pressure at the ankle after doing heal raises (called exercise ABPI)
•Blood pressure at the big toe (called toe-brachial pressure index or TBPI)
•Visible blood flow waveform (called Doppler)
•Audible blood flow waveforms (called Doppler)In some centres we will also test the performance of an additional sixth test. We have developed this
test and studied its performance in a study of 305 patients. In this study we found that the new test was
very accurate. It consists of an ultrasound test at the ankle, using a sensor and gel on the skin.The second visit will take place within 2-weeks of the first visit. In the second visit, which will take 30-
minutes, patients will have a more detailed scan of their blood vessels in their leg using a computed
tomography angiography (CTA) or magnetic resonance angiography (MRA) scan. The results from the
bedside tests will be compared to the results of the CTA or MRA to identify the most accurate test.Results Summary
Why did we conduct this research?
The detection of poor circulation, known as peripheral arterial disease (PAD), in patients with diabetes is difficult. A number of tests exist to detect PAD, however, there is confusion as to which is the gold standard. The DM PAD study determined the diagnostic performance of a number of bedside tests for the diagnosis of PAD in patients with diabetes.What did we do?
604 patients with a known history of diabetes at sixteen primary and secondary National Health Service (NHS) centres in the UK took part. Bedside tests (audible handheld Doppler, visual handheld Doppler, blood pressure measurements at the arm and ankle, blood pressure measurements at the arm and ankle following repetitive heal raises and blood pressure measurements at the big toe) for the diagnosis of PAD in patients with diabetes will be compared to reference tests (computed tomography angiography (CTA) or magnetic resonance angiography (MRA) scan).What did we find?
Each of the five routinely used bedside tests, showed low sensitivities. Overall, none of the tests demonstrated an acceptable combination of sensitivity or specificity. Combining different tests together did improve sensitivities, but many cases of PAD were still missed (confirmed via the reference scan).What could be done next?
Future work may involve a review of how PAD is diagnosed in patients with diabetes. It may be necessary to bypass bedside tests in favour of more reliable imaging, such as full lower limb duplex ultrasound.REC name
London - Central Research Ethics Committee
REC reference
21/PR/1221
Date of REC Opinion
13 Oct 2021
REC opinion
Further Information Favourable Opinion