Prevention Of Primary Foot Ulcers in High-risk Diabetes Patients (PROFOUND)

Prevention Of Primary Foot Ulcers in High-risk Diabetes Patients (PrOFoUnD): A Cluster Randomised Trial of 3D Printed Insoles Versus Standard Care

This is a primary prevention study which aims to assess reduction in the rate of diabetic foot ulcers in patients with high-risk diabetic feet using 3D printed insoles compared to standard care

Once a patient with diabetes develops a foot ulcer 80% are likely to have a lower limb amputation in the future. Amputation carries a considerable burden of cost and impaired quality of life (QOL) and is associated with a 5-year mortality rate of 70%. Once a patient develops an ulcer they remain at high risk for life and are likely to suffer considerable morbidity, debilitation, reduced quality of life and numerous attendances with health care professionals including emergency hospital presentation. There are significant costs associated with the management of diabetes foot ulcers (DFU) which accounts for £1 billion of NHS funding and an average weekly care cost of £208 per person. Both diabetes ulcers and amputation for the most part are preventable providing that patients have effective glycaemic control, regular foot assessments, care for their feet appropriately and wear appropriate footwear or orthotic wear to prevent ulceration. The focus of this initiative is to utilise digital capability by 3D scanning systems in the community for the provision of highly cost-effective 3D printed soles for shoes which distribute the pressure on the feet whilst having the flexibility of being used in general footwear, thus improving compliance. The cost of these soles is very low at approximately £40 for two pairs. More complex orthotics cost on average £525 each. Scanners and software are likely to be offered free if this is scaled up. The investigators are proposing to work closely with podiatrists in local foot protection services to assess a number of patients at high risk of foot ulcer and deliver a care bundle, which will include assessment, education around both foot care and promoting structured education and 3D sole provision. The study aims to assess reduction in the rate of diabetic foot ulcers in patients with high-risk diabetic feet using 3D printed insoles compared to standard care. The secondary outcome measures will be improvement in standardised QOL measures. 450 diabetes patients with high-risk feet would be recruited who would be prepared to wear the custom made 3D printed insoles on a regular basis (Intervention group). The control group will be formed of 450 diabetes patients with high-risk feet who will receive standard care.

As this study involves a complex intervention in the form of a pathway, we chose a cluster randomisation design to mitigate the risk of contamination across the groups. The podiatry units will find it much easier to follow one pathway for all participants in their sites. We also reduce the cost by halving the number of foot scanners required to be purchased (and the staff training required) for the study by using cluster randomisation.

6 sites out of a total of 12 will act as the intervention sites. 450 Patients with high risk of primary DFUs defined by peripheral sensory neuropathy and callus formation or critical limb ischaemia or on renal replacement therapy will be cluster randomised to be provided with bespoke 3-D printed insoles.

6 sites out of a total of 12 will act as the control sites providing standard care. 450 Patients with high risk of primary DFUs defined by peripheral sensory neuropathy and callus formation or critical limb ischaemia or on renal replacement therapy will be cluster randomised to standard care

Imprints are low-cost, bespoke, 3D-printed orthotics designed to prevent diabetic foot ulceration by redistributing and lowering peak foot pressures. This is achieved by using different density zones designed specifically for the patient. The patient's foot shape and pressure zone are capture by a 3D imaging system. Once scanned the software automatically identifies the peak pressure zones, matches these with the correct material and stiffness (densities), fits the insole arch to the patient and generates the insole. The imprints insole is divided into four pressure zones: heel, midfoot, metatarsal head region and toes. These zones are printed with different stiffness to account for the difference in loading between them. The design of the pressure zones is automatically matched to the shape of each individual foot with the help of the 3D scan.

Inclusion Criteria: Diagnosis of diabetes (type 1 or 2) Aged ≥18 Peripheral sensory neuropathy assessed by 10-gram monofilament With Signs of abnormal loading as indicated by callus formation or hyperaemia Or limb ischaemia as evidenced by intermittent claudication /non-palpable pulses / history of vascular intervention Or on renal replacement therapy Exclusion Criteria: Patients currently prescribed with or in need of therapeutic footwear Active or history of foot ulcer Active Charcot's neuroarthropathy History of major operation in the foot including amputation, Local / systemic symptoms of infection, severe illness that would make 12 month survival unlikely Unable to provide informed consent Inability to follow the study instructions (as judged by the recruiting clinician).