Development of a self-monitoring tool for diabetic foot prevention using smartphone-based thermography: Plantar thermal pattern changes and usability in the home environment.

Thermography is a well-known risk-assessment tool for diabetic foot ulcers but is not widely used in the home setting due to the influence of the complicated home environment on thermographic images. This study investigated changes in thermographic images in complicated home environments to determine the feasibility of smartphone-based thermography in home settings. Healthy volunteers (age > 20 years) were recruited and required to take plantar thermal images using smartphone-based thermography attached to a selfie stick at different times of the day for 4 days. The thermal images and associated activities and environmental factors were then analyzed using content analysis. Areas with the highest temperature on the plantar thermal images were described and categorized. Device usability was evaluated using 10-point Likert scales, with 10 representing the highest satisfaction. A total of 140 plantar thermal images from 10 participants were analyzed. In 12 classifications, the three commonest patterns based on the highest temperature location were medial arch (42.1%), whole plantar (10.7%), and forefoot and medial arch (7.9%). The medial arch pattern is most frequently seen after awakening (67.5%) compared to other time points. Device usability was rated 7.5 out of 10 on average. This study was the first to investigate the plantar thermal patterns in the home settings, and the medial arch pattern was the most common hot area, which matches previous findings in well-controlled clinical settings. Therefore, smartphone-based thermography may be feasible as a self-assessment tool in the home setting.

Evaluation of foot ulcer incidence in diabetic patients at a diabetic foot ulcer prevention clinic over a 10-year period.

The present study aimed to evaluate diabetes patients over a 10-year period that visited our outpatient clinic for prevention of diabetic foot ulcers and then investigate the incidence and aetiology of diabetic foot ulcers. The Department of Diabetes and Metabolic Diseases of a university hospital was in charge of the clinic that provided diabetes patients with individual education via the use of visualisation techniques. In this prospective cohort study, a total of 942 diabetes patients who visited the clinic were evaluated for neuropathy, angiopathy and medical history between November 2006 and March 2017. Using the patients' medical records, diabetic foot ulcer development was evaluated between the day of the first visit and December 31, 2018, with 20 out of 942 participants developing these ulcers. Over a period of 12, 60 and 120 months, the diabetic foot ulcer cumulative incidence was 0.2%, 2.4% and 5.8%, respectively. A history of diabetic foot ulcers and the male sex were shown by a Cox regression analysis to be correlated with diabetic foot ulcer development (Hazard Ratio [HR] 11.55, 95%CI 4.600-29.004, p < 0.001; and HR 3.55, 95%CI 1.031-12.196, p = 0.045, respectively). However, only five out of 20 participants with ulceration returned to the clinic for re-examination. In conclusion, a 12-month evaluation showed there was a low incidence of diabetic foot ulcers. These results might suggest that patients with a diabetic foot ulcer history need to undergo at least an annual follow-up in order to further reduce diabetic foot ulcer incidence, although studies involving control groups needs to be conducted, in presenting these as evidence.

Factors Associated with the Local Increase of Skin Temperature, 'Hotspot,' of Callus in Diabetic Foot: A Cross-Sectional Study.

BACKGROUND: Increased local skin temperature (hotspot) on a callus site as detected by thermography is a well-known precursor of diabetic foot ulcers. This study aimed to determine the factors associated with callus hotspots in order to predict the risk of callus hotspots and then provide information for specific interventions. METHODS: In this cross-sectional study, 1,007 patients' data from a diabetic foot prevention clinic between April 2008 and March 2020 were used. Data regarding patients' characteristics, foot calluses, and callus hotspots were collected and analyzed. Callus and callus hotspot were confirmed from foot photos and thermographs, respectively. A callus hotspot was defined as a relative increase in temperature compared to the skin surrounding the callus on the thermograph. Plantar pressure was measured with a pressure distribution measurement system. A generalized linear mixed model was used to identify the factors associated with callus hotspots. RESULTS: Among the 2,014 feet, 28.5% had calluses, and 18.5% of feet with calluses had callus hotspots. The factors associated with callus hotspots were number of calluses (Adjusted odds ratio (aOR): 1.540, P = .003), static forefoot peak plantar pressure (SFPPP) (aOR: 1.008, P = .001), and body mass index (aOR: 0.912, P = .029). CONCLUSIONS: Patients with a higher SFPPP were more likely to have callus hotspots suggesting that SFPPP might contribute to callus inflammation. SFPPP has the potential to be a useful predictor of callus hotspots in people with diabetes and at the same time provide information for off-loading interventions to prevent callus hotspots.

Prevention of diabetic foot ulcers using a smartphone and mobile thermography: a case study.

OBJECTIVE: Early identification of pre-ulcerative pathology is important to preventing diabetic foot ulcers (DFU), but signs of inflammation are difficult to detect on the feet of patients with diabetic neuropathy due to decreased sensation. However, infrared thermography can objectively identify inflammation. Therefore, a device that allows patients to visualise thermograms of their feet might be an effective way to prevent DFU. We aimed to determine the effects of a novel self-monitoring device to prevent DFU using a thermograph attached to a smartphone. METHOD: A self-monitoring device comprising a mobile thermograph attached to a smartphone on a selfie stick was created, and its effects in two patients with diabetic neuropathy and foot calluses assessed. RESULTS: For one patient, he understood that walking too much increased the temperature in the skin of his feet (a sign of inflammation). The other patient could not detect high-risk findings, because the temperature of his skin did not increase during the study period. CONCLUSION: This device might provide self-care incentives to prevent DFU, although some issues, such as the automatic detection of high-risk thermographic changes, need to be improved.

Factors Associated with Callus Formation in the Plantar Region through Gait Measurement in Patients with Diabetic Neuropathy: An Observational Case-Control Study.

Callus has been identified as a risk factor leading to severe diabetic foot ulcer; thus, it is necessary to prevent its formation. Callus formation under the first, second, and fifth metatarsal heads (MTHs) is associated with external forces (pressure and shear stress) during walking. However, the gait factors increasing the external forces remain undetermined. Thus, this study aims to identify the factors increasing the external forces to prevent callus formation. In 59 patients with diabetic neuropathy wearing their usual shoes, the external forces, and the lower extremity joint angles were measured using MEMS force sensors and motion sensors. The external forces and their relationship with the lower extremity joint angles and footwear size were determined. Risk factors causing high external forces on the first MTH included small flexion of the knee joint (p = 0.015) and large ankle pronation motion (p = 0.034) to obtain propulsion. For the second MTH, wearing excessively long footwear was identified (p = 0.026). For the fifth MTH, high external force was related to tight width footwear (p = 0.005). An effective intervention for preventing callus formation for the first MTH would involve assisting the push-off foot motion using rocker-sole footwear or gait training. For the second and fifth MTHs, wearing appropriate size footwear would be effective.

Skin characteristics associated with foot callus in people with diabetes: A cross-sectional study focused on desmocollin1 in corneocytes.

AIM: The purpose of this study was to investigate the degradation of desmocollin-1 (DSC1), a member of the desmosomal cadherin family in patients with diabetes, as well as the factors associated with the suppression of DSC1 degradation. METHODS: This cross-sectional study included 60 cases of foot callus involving 30 patients with diabetes (DM) and 30 matched volunteers without diabetes (non-DM). DSC1 degradation in samples from debrided calluses was analysed using western blotting. Skin hydration, a factor reported to suppress DSC1 degradation, was measured using a mobile moisture device. RESULTS: Full-length DSC1 (approximately 100 kDa) was detected in six participants only in the DM group, and no relationship was found between the suppression of DSC1 degradation and decreased skin hydration in the DM group. There was no significant difference in skin hydration values between the DM and non-DM groups. CONCLUSION: DSC1 degradation was suppressed in the DM group. There was no relationship between the suppression of DSC1 degradation and decreased skin hydration in the DM group. Current external force callus care would not be sufficient. This study highlights the need to develop novel callus care to enhance the degradation of DSC1.

The association between health literacy levels and patient-reported outcomes in Japanese type 2 diabetic patients.

OBJECTIVES: The aim of this study is to empirically examine a full pathway model of health literacy, and health and well-being outcomes among patients with type 2 diabetes. METHODS: A three-wave longitudinal survey was administered to 148 patients with diabetes. Covariance structure analysis was conducted to create a path diagram, with health literacy and burden of medical expenses included as independent variables and with psychosocial factors, behaviors, and health and well-being outcomes included as dependent variables. RESULTS: The model fit indices showed a comparative fit index of 0.985 at baseline, 0.959 after 3 months, and 0.948 after 6 months, with a root mean square error of approximation of 0.040 at baseline, 0.079 after 3 months, and 0.085 after 6 months. There were 14 significant paths across the three time points between health literacy and understanding of diabetes care, self-efficacy, communication with doctors, and medication adherence. CONCLUSION: The model fitness index showed an adequate result. Health literacy was significantly positively associated with understanding of diabetes care, self-efficacy, communication with doctors, and medication adherence. Health literacy had a direct positive influence on medication adherence and possibly an indirect positive influence on exercise/diet via self-efficacy. The results were generally consistent across the three time points, suggesting good reliability of the models. Improving health literacy may lead to better self-management of diabetes and favorable health outcomes.

Differences Between Patient-Reported Versus Clinician-Observed Nonulcerative Signs and Symptoms of the Foot in Patients With Diabetes Mellitus.

PURPOSE: The primary aim of this study was to compare patient reported versus clinician-observed nonulcerative foot conditions in patients attending a diabetic foot clinic and deemed at risk for diabetic foot ulcers. DESIGN: Retrospective review of medical records. SUBJECTS AND SETTING: The medical records of 126 patients with diabetes mellitus and deemed at risk for developing diabetic foot ulcers were reviewed. All patients received care from a diabetic foot outpatient clinic in a university-based hospital in Tokyo, Japan, between November 2008 and October 2009. METHODS: We compared patients' self-identified foot complaints with clinically observable conditions affecting the feet of these individuals with diabetes mellitus. Patients' medical records were retrieved, and patient complaints and identified preulcerative signs of the foot were documented. All clinical observations were made by nurse specialists with knowledge of diabetic foot conditions. Nonulcerative diabetic foot conditions we observed included calluses, corns, abnormal nails, fissures, tinea pedis, and tinea unguium. Patient sensitivity to correctly identify these signs was calculated using the following formula: patient-reported foot signs divided by clinically identified preulcerative signs. RESULTS: Patient sensitivity for identifying nonulcerative signs varied based on the foot condition was 51.4% for calluses, 47.8% for pincer nails, 44.4% for corns, 33.3% for fissures, 19.4% for nail abnormalities, 3.9% for scales/maceration between the toes, 2.6% for interdigital tinea pedis, and 18.2% for tinea unguium. CONCLUSION: These findings suggest that persons with diabetes vary in their awareness of conditions affecting their feet and enhancing their risk for the development of diabetic foot ulcers. We recommend additional education on foot-related self-care including how often to observe their feet and how to recognize symptoms that may elevate their risk for diabetic foot ulcers.

The Association between Tinea Pedis and Feet-Washing Behavior in Patients with Diabetes: A Cross-sectional Study.

OBJECTIVES: To examine the correlations between elements of feet-washing behavior, presence of tinea pedis (TP), and patients' background characteristics in order to identify a concrete intervention method to prevent TP. DESIGN AND PARTICIPANTS: A cross-sectional study of 30 patients with diabetes (16 with TP) who were admitted to or visited the university hospital. MAIN OUTCOME MEASURES: The presence of TP was confirmed by the detection of dermatophytes by direct microscopy. Data on elements of feet-washing behavior, such as scrubbing between the toes, were collected by observing recorded videos of participants normally washing their feet as they do at home. The patients' background characteristics included demographic data; diabetes-related factors; patient knowledge regarding diabetes, foot problems, and TP prevention; purpose for feet washing; and any difficulties in feet washing. MAIN RESULTS: The number of times patients scrubbed between their toes while washing with soap was significantly lower in patients with TP (odds ratio, 0.95; P = .036; with a cutoff value of 35 times) and those who had difficulty in reaching their feet with their hands (B = -14.42, P = .041). CONCLUSIONS: An effective foot-washing protocol should include specific instructions for patients to scrub between their toes at least 35 times in all 8 spaces while washing with soap. Appropriate advice is also needed for individuals who have difficulty reaching their feet with their hands. Education about appropriate foot-washing behavior may potentially prevent TP.

Thermographic findings in a case of type 2 diabetes with foot ulcer due to callus deterioration.

ABSTRACT: A number of studies have reported the usefulness of monitoring skin temperature at local points in reducing the risk of ulceration. Thermography has the advantage of being able to visualize morphological temperature distribution. We reported that inflammation was detected by thermography in 10% of diabetes mellitus (DM) patients with foot calluses, and the area in which increased skin temperature was observed was limited to the callus. However, no reports have described thermographic findings of calluses deteriorating into foot ulcers. We report a case monitoring the skin temperature distribution using thermography, which might be useful for predicting ulceration. CASE: A 53-year-old male patient, diagnosed with type 2 DM, was treated with insulin therapy. The duration of DM was 4 years. He was also diagnosed with dyslipidemia and hypertension. Using thermography, the skin temperature was evaluated in the patient with calluses on the 5th metatarsal heads. Areas of increased skin temperature were observed, involving not only the callused part, but also the plantar arch. We shaved his calluses once a month and explained the importance of his therapeutic shoes to prevent the ulcers. After 43 months, an ulcer developed. DISCUSSIONS: Thermographic findings of an extended area of increased skin temperature not limited to the callus may suggest the progression of a callus to ulcer. Expansion of the area of increased skin temperature might show the inflammation or infection extending along the fascia. Based on these findings, thermography could provide a useful assessment of callus in DM patients with a high risk of progression.

Factors Associated With Callus in Patients with Diabetes, Focused on Plantar Shear Stress During Gait.

BACKGROUND: The aim of this study is to identify whether plantar shear stress in neuropathic patients with diabetes with callus is increased compared with those without callus. METHOD: The differences in foot deformity, limited joint mobility, repetitive stress of walking, and ill-fitting shoes between patients with callus and those without callus were also determined. Subjects were recruited from the Diabetic Foot Outpatient Clinic. A newly developed in-shoe measurement system, which has flexible and thin insoles, enabled measurement of both plantar pressure and shear stress simultaneously when subjects walked as usual on a 10 m walkway. RESULTS: It was found that plantar shear stress adjusted for weight during the push-off phase was increased by 1.32 times in patients with callus compared with those without callus (mean ± SD: 0.0500 ± 0.0160 vs 0.0380 ± 0.0144, P = .031). Moreover, hallux valgus deformity, reduction in dorsiflexion of the ankle joint and increase in plantar flexion were showed in feet with callus. Increased plantar shear stress may be caused by gait change that patients having callus push off with the metatarsal head instead of the toe as a result of foot deformity and limited joint mobility. CONCLUSIONS: It was found that plantar shear stress adjusted for weight during the push-off phase was increased in patients with callus compared with those without callus by using the newly developed measurement system. These results suggest that reduction of plantar shear stress during the push-off phase can prevent callus formation in neuropathic patients with diabetes.

Shear Stress-Normal Stress (Pressure) Ratio Decides Forming Callus in Patients with Diabetic Neuropathy.

Aim. Callus is a risk factor, leading to severe diabetic foot ulcer; thus, prevention of callus formation is important. However, normal stress (pressure) and shear stress associated with callus have not been clarified. Additionally, as new valuables, a shear stress-normal stress (pressure) ratio (SPR) was examined. The purpose was to clarify the external force associated with callus formation in patients with diabetic neuropathy. Methods. The external force of the 1st, 2nd, and 5th metatarsal head (MTH) as callus predilection regions was measured. The SPR was calculated by dividing shear stress by normal stress (pressure), concretely, peak values (SPR-p) and time integral values (SPR-i). The optimal cut-off point was determined. Results. Callus formation region of the 1st and 2nd MTH had high SPR-i rather than noncallus formation region. The cut-off value of the 1st MTH was 0.60 and the 2nd MTH was 0.50. For the 5th MTH, variables pertaining to the external forces could not be determined to be indicators of callus formation because of low accuracy. Conclusions. The callus formation cut-off values of the 1st and 2nd MTH were clarified. In the future, it will be necessary to confirm the effect of using appropriate footwear and gait training on lowering SPR-i.

Association between Washing Residue on the Feet and Tinea Pedis in Diabetic Patients.

Tinea pedis (TP) may lead to the development of foot ulcers in diabetic patients; thus, its prevention in diabetic patients is important. TP occurs after dermatophytes on the skin scales of TP patients attach to the feet. Therefore, it is necessary to remove the scales and dermatophytes, and this can be performed using various methods, including foot washing. This study aimed to objectively examine the association between the presence of TP and foot-washing habits. We included 33 diabetic patients, and, of these, 17 had TP. The presence of washing residue on the feet was determined by applying a fluorescent cream to the participants' feet, and images of the feet were captured under ultraviolet light before and after foot washing. Our results showed that diabetic patients with TP had higher levels of washing residue on their feet than those without TP. The importance of washing feet to prevent TP needs to be emphasized through educational programs for diabetic patients. Furthermore, the development of an effective foot-washing technique is essential.

Elevated plantar pressure in diabetic patients and its relationship with their gait features.

PURPOSE: High plantar pressure is a major risk factor for diabetic foot ulcers. The relationship between plantar pressure and foot mobility has been investigated in some studies. However, when the foot is in motion, foot mobility is only a small feature of the gait. Therefore, we investigated relationship between high plantar pressure and gait and also studied the motion of the trunk. In addition, we investigated the relationship between gait and patient characteristics to identify patients at high-risk of developing diabetic foot ulcers. METHODS: The relationships between elevated plantar pressure, gait features, and patient characteristics were analyzed. Plantar pressure distribution in the stance phase was divided on the four plantar segments. Elevated plantar pressure was defined as being more than the mean plus one standard deviation of the corresponding segment in non-diabetic subjects. Plantar pressure distribution was measured by an F-scan system, and gait features were measured using wireless motion sensors attached to the sacrum and feet. Patient characteristics were obtained from medical records or by interview. RESULTS: Small roll and yaw motions of the body and yaw motion of the foot during the mid-stance phase were related to the elevated plantar pressure in 57 diabetic patients. Furthermore, these gait features were related to sensory neuropathy, diabetes duration, patient weight, toe-gap force, and ankle range of motion. CONCLUSION: Given our findings, it may be possible to prevent diabetic foot ulcers by increasing foot motion during the mid-stance phase. Passive exercise aimed at expanding ankle range of motion in patients with sensory neuropathy or long-standing diabetes may assist in achieving this.

Morphological pattern classification system for plantar thermography of patients with diabetes.

BACKGROUND: A plantar temperature distribution can be obtained by thermography; however, the advantage has not been effectively utilized in the past. We previously proposed a classification method based on the angiosome concept, but the method was insufficient because it was too subjective and complicated for clinicians. In this study, we propose a new classification system of plantar forepart thermographic patterns using an image segmentation technique. METHODS: A cross-sectional observational study was conducted including 32 healthy volunteers and 129 patients with diabetes mellitus (DM). Individual thermographic variations and trends were evaluated. A comparison was conducted between the patterns obtained by our previous angiosome-based research and the patterns found by the new classification system. RESULTS: The system objectively found wider variations of the plantar forepart thermographic patterns in the patients with DM compared with those in the control subjects. In patients with DM, the system showed that the whole-high pattern was most frequent (46%), followed by the butterfly pattern (12%). In the control group, the butterfly pattern was most frequent (44%), followed by the whole-high pattern (19%). Both ankle and toe brachial indices were higher in feet with high temperature area in the inner side of the plantar. CONCLUSIONS: Thermographic patterns found by the new computer-based system were similar to those obtained in our previous subjective work. The classification system found forefoot-low pattern and tiptoe-low pattern objectively. The system based on infrared thermography will be a screening tool to assess circulatory status in daily foot care of patients with DM.

Relationship between elevated plantar pressure of toes and forefoot and gait features in diabetic patients.

This cross-sectional observational study is to reveal what kind of gait feature is relevant to elevated segment and its plantar pressure for prevention of diabetic foot ulcers. In 57 diabetic patients, the relationship between elevated plantar pressure and gait features was analyzed. To conduct this investigation, a simultaneous measurement system of plantar pressure and gait features was constructed. Plantar pressure distribution was measured by F-scan with customized footwear, and gait features were mainly measured using wireless motion sensors attached to the sacrum and feet. Several gait features of small rolling during the mid-stance phase were relevant to the elevated plantar pressure.

Factors associated with deep foot fissures in diabetic patients: a cross-sectional observational study.

BACKGROUND: Foot ulcers can develop from fissures in patients with diabetes. It is generally considered that fissures can develop with dry skin due to decreased perspiration associated with autonomic neuropathy. Especially, deep fissures that extend into the dermis may have a higher risk of ulceration than superficial fissures because of damage of skin barrier function. However, distinctions between superficial and deep fissures have not been well described, and specific factors involved in their development are generally unknown. OBJECTIVE: To investigate factors associated with the superficial and deep foot fissures in patients with diabetes. DESIGN AND METHODS: This cross-sectional observational study involved 578 patients with diabetes evaluated at a university hospital between September 2007 and March 2008. Patients with foot ulcers or foot defects due to amputation were excluded. Superficial fissures were defined as narrow skin cracks limited to the epidermis. Deep fissures were defined as narrow, deep, linear skin cracks extending to the dermis, possibly with higher ulceration risk than superficial fissures. Logistic regression analysis was performed to analyze factors associated with the depth (superficial or deep) of foot fissures. RESULTS: The prevalence of superficial fissures was 9.0%, and that of deep fissures was 3.8%. Presence of superficial fissures was correlated with autonomic neuropathy (OR 2.35, 95% CI 1.20-4.59, p=0.012). Notably, presence of deep fissures was correlated with autonomic neuropathy and angiopathy (OR 2.88, 95% CI 1.11-7.48, p=0.030; and OR 3.29, 95% CI 1.30-8.35, p=0.012, respectively). CONCLUSIONS: Our new finding of a correlation between deep fissures and angiopathy suggests that control of blood supply should be effective for preventing deep fissures prone to ulceration. In the future, elucidation of the mechanism of the angiopathy-induced deep fissures will be needed to promote more effective preventive care of fissures.