Extracorporeal Shockwave Therapy for Diabetic Foot Ulcers

There is an urgent need for better treatments for diabetic foot ulcers. Despite current best treatment, diabetic foot ulcers can be very difficult to heal, often taking months to heal and some never do. Even after healing ulcers return in up to 60% of people. In England someone undergoes an amputation of part of their foot every 2 hours and every 4 hours someone loses their leg due to diabetic foot ulcers. People are rarely able to be as active as before. This seriously affects their work, finances and quality of life.

This research is going to look at a new therapy called Extracorporeal Shockwave Therapy. Extracorporeal shockwave therapy (high power soundwaves) is a non-invasive treatment that is delivered directly to the ulcer and may improve healing. However, the effectiveness of shockwave therapy and the optimum dose is unknown. We will investigate if shockwave therapy improves diabetic foot ulcer healing. To do this we will undertake a randomised controlled trial. The trial will randomly allocate people (who are eligible to take part and consent) into one of three groups: sham shockwave therapy, low dose shockwave therapy and high dose shockwave therapy. The patient will not know which group they are in. The researcher collecting wound data will not know which group the patient is in. This is to ensure we and the patient do not influence the results of the study. This is a rigorous way of comparing new treatments to existing ones.

The purpose of the pilot trial is to provide information to be able to repeat this trial again with a larger number of people. This pilot trial will help identify any problems and address any issues before the main trial starts. This minimises the risk of wasting money and people's time.

The aim of this study is to:

• Carry out a preliminary (pilot) trial comparing sham (not active) shockwave therapy, low number of shockwaves and high number of shockwaves on diabetes foot ulcers
• To understand beliefs, concerns, ideas and experience of shockwave therapy amongst patients and clinicians

The research has been co-designed by patients and their families with experience of diabetic foot ulcers.

Pilot Trial:

The aim of the pilot trial is to see whether we can recruit enough patients to the study, how many patients remain in the study and reasons why patients leave the trial. It will also test whether we are collecting the information (data) in the right way to answer the research question. This is to make sure that the main trial is successful. Ninety patients who have a diabetic foot ulcer will be randomly assigned to one of the three treatment groups:

• High dose shockwave therapy
• Low dose shockwave therapy
• 'Sham' shockwave therapy

Each treatment will be delivered in a 3x30minute sessions over a 7 day period. All patients will receive usual ulcer care. Face to face follow up appointments will be at 6 weeks, 12 weeks and 24 weeks after study entry to measure ulcer healing, changes in quality of life and health resource use.

Interviews: Patients who are eligible to take part in the trial will be invited to an interview, to explore their reasons for (or for not) taking part, experience undergoing shockwave therapy and thoughts about being in the trial. This is to identify aspects of the trial which patients considered positive/negative so improvements can be made to the main trial. It will also help to improve the main trial and ensure our research is inclusive. Informal interviews, lasting around 30minutes, will be undertaken to explore patient opinion of shockwave therapy, experience of taking part in the trial, reasons patients do not want to take part and clinician attitudes to shockwave therapy. 24 patients and 8 clinicians will be invited to take part.

Inclusion criteria

• At least one unhealed diabetic foot ulcer below the level of the medial malleoli that has been present for more than 4 weeks
• Absolute toe pressure greater than or equal to 50mmHg or an Ankle Pressure Brachial Index (ABPI) equal to or greater than 0.7(24, 25)
• Capacity to consent to participate in the trial and given written informed consent
• Willing to be randomised to either sham, low-dose or high-dose ESWT
• Willing to consent to photography of the index DFU
• Willing to comply with the follow up schedule

Exclusion criteria

• Interdigital index ulcer. This is because the ESWT delivery paddle does not fit between digits.
• Currently on or planned treatment for osteomyelitis.
• Currently taking any therapeutic anticoagulation medications. This includes novel oral anticoagulants, therapeutic doses of heparin and vitamin-K antagonists. This is a contraindication to ESWT.
• Diagnosis of malignancy in the treatment area or haematological, disseminated or lymphatic malignancy. This is a contraindication to ESWT.
• All who are pregnant, trying to conceive or breastfeeding. This is a contraindication to ESWT.
• Active participants in other trials that may conflict with the study outcomes, for example any other wound care trials.