Site-Specific, Critical Threshold Barefoot Peak Plantar Pressure Associated with Diabetic Foot Ulcer History: A Novel Approach to Determine DFU Risk in the Clinical Setting.

Background and Objectives: Barefoot peak plantar pressures (PPPs) are elevated in diabetes patients with neuropathic foot ulcer (DFU) history; however, there is limited reported evidence for a causative link between high barefoot PPP and DFU risk. We aimed to determine, using a simple mat-based methodology, the site-specific, barefoot PPP critical threshold that will identify a plantar site with a previous DFU. Materials and Methods: In a cross-sectional study, barefoot, site-specific PPPs were measured with normal gait for patients with DFU history (n = 21) and healthy controls (n = 12), using a validated carbon footprint system. For each participant, PPP was recorded at twelve distinct plantar sites (1st-5th toes, 1st-5th metatarsal heads (MTHs), midfoot and heel), per right and left foot, resulting in the analysis of n = 504 distinct plantar sites in the diabetes group, and n = 288 sites in the control group. Receiver operator characteristic curve analysis determined the optimal critical threshold for sites with DFU history. Results: Median PPPs for the groups were: diabetes sites with DFU history (n = 32) = 5.0 (3.25-7.5) kg/cm2, diabetes sites without DFU history (n = 472) = 3.25 (2.0-5.0) kg/cm2, control sites (n = 288) = 2.0 (2.0-3.25) kg/cm2; (p < 0.0001). Diabetes sites with elevated PPP (>6 kg/cm2) were six times more likely to have had DFU than diabetes sites with PPP ≤ 6 kg/cm2 (OR = 6.4 (2.8-14.6, 95% CI), p < 0.0001). PPP > 4.1 kg/cm2 was determined as the optimal critical threshold for identifying DFU at a specific plantar site, with sensitivity/specificity = 100%/79% at midfoot; 80%/65% at 5th metatarsal head; 73%/62% at combined midfoot/metatarsal head areas. Conclusions: We have demonstrated, for the first time, a strong, site-specific relationship between elevated barefoot PPP and previous DFU. We have determined a critical, highly-sensitive, barefoot PPP threshold value of >4.1 kg/cm2, which may be easily used to identify sites of previous DFU occurrence and, therefore, increased risk of re-ulceration. This site-specific approach may have implications for how high PPPs should be investigated in future trials.

Multicenter, randomized controlled, observer-blinded study of a nitric oxide generating treatment in foot ulcers of patients with diabetes-ProNOx1 study.

The aim of this multicenter, prospective, observer-blinded, parallel group, randomized controlled trial was to assess the safety and efficacy of EDX110, a nitric oxide generating medical device, in the treatment of diabetic foot ulcers in a patient group reflecting "real world" clinical practice compared against optimal standard care. Participants were recruited from ten hospital sites in multidisciplinary foot ulcer clinics. The ulcers were full thickness, with an area of 25-2,500 mm2 and either a palpable pedal pulse or ankle brachial pressure index > 0.5. Infected ulcers were included. Treatment lasted 12 weeks, or until healed, with a 12-week follow-up period. Both arms were given optimal debridement, offloading and antimicrobial treatment, the only difference being the fixed used of EDX110 as the wound dressing in the EDX110 group. 135 participants were recruited with 148 ulcers (EDX110-75; Control-73), 30% of which were clinically infected at baseline. EDX110 achieved its primary endpoint by attaining a median Percentage Area Reduction of 88.6% compared to 46.9% for the control group (p = 0.016) at 12 weeks in the intention-to-treat population. There was no significant difference between wound size reduction achieved by EDX110 after 4 weeks and the wound size reduction achieved in the control group after 12 weeks. EDX110 was well tolerated. Thirty serious adverse events were reported (12 in the EDX110 group, of which 4 were related to the ulcer; 18 in the control group, of which 10 were related and 1 possibly related to the ulcer), with significant reduction in serious adverse events related to the ulcer in EDX group. There was no significant difference in adverse events. This study, in a real world clinical foot ulcer population, demonstrates the ability of EDX110 to improve healing, as measured by significantly reducing the ulcer area, compared to current best clinical practice.

An intelligent insole system with personalised digital feedback reduces foot pressures during daily life: An 18-month randomised controlled trial.

AIMS: High plantar pressure is a major risk factor in the development of diabetic foot ulcers (DFUs) and recent evidence shows plantar pressure feedback reduces DFU recurrence. This study investigated whether continued use of an intelligent insole system by patients at high-risk of DFUs causes a reduction in plantar pressures. METHODS: Forty-six patients with diabetic peripheral neuropathy and previous DFU were randomised to intervention (IG) or control groups (CG). Patients received an intelligent insole system, consisting of pressure-sensing insoles and digital watch. Patients wore the device during all daily activity for 18-months or until ulceration, and integrated pressure was recorded continuously. The device provided high-pressure feedback to IG only via audio-visual-vibrational alerts. High-pressure parameters at the whole foot, forefoot and rearfoot were compared between groups, with multilevel binary logistic regression analysis. RESULTS: CG experienced more high-pressure bouts over time than IG across all areas of the foot (P < 0.05). Differences between groups became apparent >16 weeks of wearing the device. CONCLUSIONS: Continuous plantar pressure feedback via an intelligent insole system reduces number of bouts of high-pressure in patients at high-risk of DFU. These findings suggest that patients were learning which activities generated high-pressure, and pre-emptively offloading to avoid further alerts.

Innovative intelligent insole system reduces diabetic foot ulcer recurrence at plantar sites: a prospective, randomised, proof-of-concept study.

BACKGROUND: Prevention of diabetic foot ulcer recurrence in high risk patients, using current standard of care methods, remains a challenge. We hypothesised that an innovative intelligent insole system would be effective in reducing diabetic foot ulcer recurrence in such patients. METHODS: In this prospective, randomised, proof-of-concept study, patients with diabetes, and with peripheral neuropathy and a recent history of plantar foot ulceration were recruited from two multidisciplinary outpatient diabetic foot clinics in the UK, and were randomly assigned to either intervention or control. All patients received an insole system, which measured plantar pressure continuously during daily life. The intervention group received audiovisual alerts via a smartwatch linked to the insole system and offloading instructions when aberrant pressures were detected; the control group did not receive any alerts. The primary outcome was plantar foot ulcer occurrence within 18 months. This trial is registered with ISRCTN, ISRCTN05585501, and is closed to accrual and complete. FINDINGS: Between March 18, 2014, and Dec 20, 2016, 90 patients were recruited and consented to the study, and 58 completed the study. At follow-up, ten ulcers from 8638 person-days were recorded in the control group and four ulcers from 11 835 person-days in the intervention group: a 71% reduction in ulcer incidence in the intervention group compared with the control group (incidence rate ratio 0·29, 95% CI, 0·09-0·93; p=0·037). The number of patients who ulcerated was similar between groups (six of 26 [control group] vs four of 32 [intervention group]; p=0·29); however, individual plantar sites ulcerated more often in the control group (ten of 416) than in the intervention group (four of 512; p=0·047). In an exploratory analysis of good compliers (n=40), ulcer incidence was reduced by 86% in the intervention group versus control group (incidence rate ratio 0·14, 95% CI 0·03-0·63; p=0·011). In the exploratory analysis, plantar callus severity (change from baseline to 6 months) was greater in re-ulcerating patients (6·5, IQR 4·0-8·3) than non-re-ulcerating patients (2·0, 0·0-4·8; p=0·040). INTERPRETATION: To our knowledge, this study is the first to show that continuous plantar pressure monitoring and dynamic offloading guidance, provided by an innovative intelligent insole system, can lead to a reduction in diabetic foot ulcer site recurrence. FUNDING: Diabetes UK and Orpyx Medical Technologies.