Title: Reducing Foot Plantar Pressure (ReFPres) in people with diabetes using an instant insole solution: a mixed methods pilot study.
Funder: Health Education England

Abstract: Background: As a common long term complication, diabetic foot disease is associated with impaired quality of life, high direct and indirect treatment costs and high rates of mortality. Reducing plantar foot pressures is one crucial aspect of optimising healing potential and preventing foot ulceration, particularly in neuropathic feet absent of protective sensation, where plantar loads and tissue stress are increased. Therapeutic footwear and insoles are utilised to reduce plantar pressures. However their effectiveness is variable difficult to predict and often evaluated by the high risk strategy of observing foot health and tissue integrity over time with frequent service provision and manufacturing delays. Aim: A pilot study to inform the development of a large scale, multi-site, randomized controlled trial to investigate the clinical and cost effectiveness of a new instant insole solution for people at high risk of diabetic neuropathic foot ulceration to instantly modify and optimise plantar pressure, with the aim of reducing risk of diabetic foot ulcer occurrence and recurrence. Research design and Methods: A mixed methods pilot double-blinded multicentre randomised controlled trial with subjects randomised to wear either an insole designed by in-shoe plantar pressure measurement technology (n=38) or a standard cushioned insole (n=38) over 3 sites (Torbay, Exeter, Solent). Participants will be followed for 3, 6 and then 12 months with recording of ulcer re-occurrence incidence, peak plantar pressure reduction outcome and patient compliance. Furthermore semi-structured interviews of (n=9) participants will be used to explore experiences of the trial to inform barriers to recruitment and retention to inform the main study development. Clinicians (n=4) involved in the delivering trial will also be interviewed to ascertain their perception and experience in providing the intervention. Analysis: The pilot study will use descriptive statistics to evaluate any difference between the 2 groups in terms of peak pressure reduction, adherence to wearing the footwear and ulceration rates. This will enable us to calculate an effect size estimate of incidence of plantar foot ulcers to inform a sample size calculation for the main RCT. Furthermore we will assess the effectiveness of the training package for clinicians delivering the intervention and the effectiveness of the intra and inter-rater reliability. In addition interviews will be recorded, transcribed and then analysed using NVivo software and thematic analysis undertaken. We will also assess whether our outcome measures are appropriate and evaluate participant compliance with the intervention. Benefits: The results of this study will inform the design of a large scale multi-centred RCT to examine the clinical and cost effectiveness of the in-shoe pressure analysis designed insole. It will aim to provide an innovative service to the diabetic population in an attempt reduce the incidence of ulcer occurrence/re-occurrence making significant savings, both financial and in quality of life for patients and the NHS. It will provide a reliable model that can be utilised by other foot protection services within the national arena.

Lay abstract: One of the common devastating, long term problems associated with diabetes is the development of foot ulcers. One type of foot ulcer that is found in approximately 50% of cases is those on the underside of the foot. These are associated with high pressure areas due to neuropathy and can be extremely debilitating. Neuropathy is a disease or dysfunction of one or more peripheral nerves, typically causing numbness or weakness and is extremely common amongst those suffering from diabetes. The differing types of neuropathy means that on many occasions people's feet gradually change shape, their skin becomes drier and the resultant lack of sensation means that they don't actually feel that they are doing extensive and serious damage to the foot. Gradually this will cause a buildup of pressure that will cause a break in the skin, or an ulcer. These problems can be extremely disabling and have a massive impact on long term survival rates and can be life changing because of a very much lower quality of living. Unfortunately in approximately 25% of cases these ulcers can further worsen and far too frequently lead to lower limb amputations. Insoles and specialist shoes are often provided to move the pressure from the high impact areas to other parts of the foot in an attempt to either heal the ulcer or reduce the risk of ulcers occurring.Some studies have already identified that the use of footwear insoles are successful in reducing these pressure points. Currently insoles are ordered for manufacture by an Orthotist who takes a mould of the patients' foot along with the necessary measurements and then sends this information off to have the insoles manufactured alongside the specialist shoes, which can happen almost anywhere in the country. At the moment this process takes anything up to 3 months and sometimes even longer. Once the new insoles are received they are given to the patient to wear and their feet are monitored over several months to determine if they have been effective in stopping/healing the ulcers developing. Unfortunately this is a lengthy procurement time and this, together with other frequent delays in providing the insoles and calculating how efficient they are in moving the pressure around the foot, is really far too long to be suitably effective. Therefore we propose a study to see how effective it is to use new technology (a scanner that actually fits inside the patient's shoe) to measure the walking pressures under the foot and then, using that resultant information, make a specialised insole that can actually be worn and taken home during the same day, removing the previous delays and having to guess how effective the insole is in reducing the pressure.Before undertaking a large trial we first need to assess it on a smaller scale to determine if the way we are testing with the new technology and new way of working is sufficiently helpful in stopping and preventing ulcers developing. Therefore we will be enlisting the help of people with experience of diabetes and neuropathy in the three selected areas of Torbay and Southern Devon, Exeter and the Solent to take part in a smaller pilot' trial. We wish to compare 2 groups of 38 people with diabetes and sensory neuropathy that have been categorised as high risk of developing a foot ulcer; one group will be given special insoles made using this new scientific method and the other will be given plain cushioned insoles. We will then be able to determine whether there is any significant difference in reducing the harmful pressure points and stopping ulcers forming between the groups over a 3, 6 and 12 month period. We will also want to interview nine of the patients and the four clinicians taking part about their experiences of taking part in the trial and whether it can be improved. We will also collect valuable data that will be used to ensure that the main trial will produce the most accurate and meaningful results.Once we have collected all of the data and gathered peoples' views of the pilot study we intend to run a large scale trial over lots of areas around the country to test this new idea. Ultimately our findings will be used to change the way that the Podiatry services around the country works to reduce the risk of people with diabetes developing foot ulcers and the terrible consequences that come with this horrible worldwide problem.

Research activity codes: 6.3 MEDICAL DEVICES
Health categories: METABOLIC AND ENDOCRINE