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20/23 Diagnostic tools to establish the presence and severity of peripheral arterial disease in people with diabetes



We understand that many people will be prioritising NHS work and supporting COVID 19 research during the current pandemic. It is NIHR policy that these should always be the priority as reinforced by our April Programme Director’s message. It is also NIHR policy to keep the future research pipeline healthy and to support the research community. The HTA programme is therefore advertising the following topics for stage 1 applications with a 16 week preparation period and deadline of 29 July 2020 unless otherwise stated. Please also note that these first stage applications do not need to contain a large amount of detail and that we only ask for estimates of costs at this stage.

Research question

In people with diabetes, what are the accuracy and cost-effectiveness of non-invasive tests to establish the presence of peripheral arterial disease of lower limbs and to assess disease severity? 

  1. Technology: Non-invasive diagnostic tests including: Ankle brachial pressure index, post exercise ankle brachial index, toe brachial index, and Doppler wave form analysis.
  2. Patient group: Adults with diabetes who have suspected peripheral arterial disease (in line with NICE CG147). Applicants should define and justify eligibility criteria.
    Applications are encouraged which include recruitment from geographic populations with high disease burden which have been historically underserved by research activity in this field.
  3. Setting: Any suitable settings. The study should examine the performance of tests in different clinical and community settings as applied in routine practice to an appropriate fidelity.
  4. Reference standard: Imaging (e.g. magnetic resonance imaging, computed tomography angiography), to be defined and justified by applicants.
  5. Study design: A diagnostic accuracy study and decision analytic model of cost-effectiveness. Applicants should explore different cut-off points for each test. The study design should be pragmatic. 
  6. Outcomes and outputs: Measures of diagnostic accuracy; estimates of cost-effectiveness; cut-off points; inter- and intra-rater reliability as appropriate in a pragmatic design; patient acceptability and suitability. Subgroup analysis (e.g. patients with/without neuropathy) may be considered if appropriate.  
    Longer-term follow up: If appropriate, researchers should consider obtaining consent from participants to allow potential future follow up through efficient means (such as routine data) as part of a separately funded study.


Peripheral arterial disease (PAD) is a cardiovascular disease that commonly affects the arteries in the legs. It is characterised by the narrowing of the arteries that results in reduced blood flow to the limbs.

PAD is a relatively common condition, especially among older people. People with diabetes or coronary artery disease and those who smoke are at increased risk of developing PAD. The most common initial symptom of PAD is leg pain while walking, known as intermittent claudication, which remains stable in most people. However, a proportion of people with PAD will experience increasingly severe symptoms with the development of critical limb ischaemia. This is a serious complication of PAD that is characterised by severely diminished blood circulation, pain, leg ulcers, tissue loss and/or gangrene. Complications specific to people with diabetes include foot problems ('diabetic foot ulcer'), which are associated with high risk of amputation. 

The diagnosis of PAD is based on clinical assessment and diagnostic tests. The most widely used test is the ankle brachial pressure index (ABPI) test, which allows the blood flow to the limbs to be evaluated. However, assessment of PAD using ABPI among people with diabetes may be challenging due to the hardening of the arteries (medial sclerosis), which is common in people with diabetes. As the arteries become incompressible, a falsely elevated ABPI may be obtained, and the diagnosis of PAD may be missed.

A recent evidence review undertaken by NICE concluded that other forms of assessment might be superior to ABPI for diagnosing PAD in people with diabetes. However, there was not enough evidence on the use of such tests (e.g. Doppler waveform analysis and toe brachial index) in this patient group. NICE therefore published research recommendations to inform future practice and any further update of its guidance on the diagnosis and management of PAD (NICE CG147).

The HTA programme therefore wishes to fund a study that will investigate the diagnostic accuracy and cost-effectiveness of various non-invasive tests for the diagnosis and assessment of PAD in people with diabetes.

Additional commissioning brief background information

A background document is available that provides further information to support applicants for this call. It is intended to summarise what prompted the call and the existing evidence base, including relevant work from the HTA and wider NIHR research portfolio. It was researched and written on the basis of information from a search of relevant sources and databases, and in consultation with a number of experts in the field. If you would like a copy please email

Making an application

If you wish to submit a Stage 1 application for this call, the online application form can be found on the Funding opportunities page.  To select this call, use the filters on the right of the screen or search using the call name and/or number.

Your application must be submitted on-line no later than 1pm on the 29 July 2020. Applications will be considered by the HTA Funding Committee at its meeting in September 2020.

Guidance notes and supporting information for HTA Programme applications are available by clicking the links.

IMPORTANT: Shortlisted Stage 1 applicants will be given eight weeks to submit a Stage 2 application. The Stage 2 application will be considered at the Funding Committee in January 2021.

Applications received electronically after 1300 hours on the due date will not be considered.

Should you have any queries please contact us:


Telephone:  Commissioning Funding Committee 02380 595510