Infrared thermography and ulcer prevention in the high‐risk diabetic foot: data from a single‐blind multicentre controlled clinical trial

Abstract

Aim To assess the usefulness of monthly thermography and standard foot care to reduce diabetic foot ulcer recurrence. Methods People with diabetes (n = 110), neuropathy and history of ≥ 1 foot ulcer participated in a single‐blind multicentre clinical trial. Feet were imaged with a novel thermal imaging device (Diabetic Foot Ulcer Prevention System). Participants were randomized to intervention (active thermography + standard foot care) or control (blinded thermography + standard foot care) and were followed up monthly until ulcer recurrence or for 12 months. Foot thermograms of participants from the intervention group were assessed for hot spots (areas with temperature ≥ 2.2°C higher than the corresponding contralateral site) and acted upon as per local standards. Results After 12 months, 62% of participants were ulcer‐free in the intervention group and 56% in the control group. The odds ratios of ulcer recurrence (intervention vs control) were 0.82 (95% CI 0.38, 1.8; P = 0.62) and 0.55 (95% CI 0.21, 1.4; P = 0.22) in univariate and multivariate logistic regression analyses, respectively. The hazard ratios for the time to ulcer recurrence (intervention vs control) were 0.84 (95% CI 0.45, 1.6; P = 0.58) and 0.67 (95% CI 0.34, 1.3; P = 0.24) in univariate and multivariate Cox regression analyses, respectively. Conclusions Monthly intervention with thermal imaging did not result in a significant reduction in ulcer recurrence rate or increased ulcer‐free survival in this cohort at high risk of foot ulcers. This trial has, however, informed the design of a refined study with longer follow‐up and group stratification, further aiming to assess the efficacy of thermography to reduce ulcer recurrence.

The Potential Role of Sensors, Wearables and Telehealth in the Remote Management of Diabetes-Related Foot Disease

“…A larger randomised trial involving 304 participants is currently examining the cost-effectiveness and cost-utility of home foot temperature monitoring [9]. Recently, a further clinical trial reported on the efficacy of foot temperature monitoring performed at only monthly intervals at an out-patient clinic, rather than at home [24]. A thermal camera was employed to identify "hot spots" in order to advise on interventions, such as reductions in physical activity and improved offloading of the concerned area [24].…”

“…Recently, a further clinical trial reported on the efficacy of foot temperature monitoring performed at only monthly intervals at an out-patient clinic, rather than at home [24]. A thermal camera was employed to identify "hot spots" in order to advise on interventions, such as reductions in physical activity and improved offloading of the concerned area [24]. The trial included 110 people with a past history of a diabetes-related foot ulcers and reported no benefit of the intervention in preventing foot ulcers or improving health-related quality of life [24].…”

“…A thermal camera was employed to identify "hot spots" in order to advise on interventions, such as reductions in physical activity and improved offloading of the concerned area [24]. The trial included 110 people with a past history of a diabetes-related foot ulcers and reported no benefit of the intervention in preventing foot ulcers or improving health-related quality of life [24]. It is possible that these contrasting findings relate to the less-frequent monitoring of foot temperature performed, which may have missed an opportunity for the early identification of at-risk patients.…”

“…Furthermore, prior clinical experience and recent reports of infrared thermography show that foot temperature rises immediately following successful revascularization in correlation with the increase in the ankle brachial pressure index [29]. Given the established effect of leg ischemia on foot temperature and the exclusion of participants with this problem from prior trials [17][18][19][20]24], the role of home foot temperature monitoring in people with PAD remains unclear. The ongoing trial of home temperature monitoring detailed above only excludes people with critical limb ischemia (defined as a systolic ankle blood pressure <50 mmHg, systolic toe blood pressure <30 mmHg or transcutaneous oxygen pressure <30 mm Hg) and therefore will better clarify the role of home temperature monitoring in people with milder forms of PAD [9].…”

Morphological Foot Model for Temperature Pattern Analysis Proposed for Diabetic Foot Disorders

“…In fact, it has been suggested that thermal asymmetry monitoring has no additional value for assessing the severity of diabetic foot infections [15]. Moreover, for patients at a high risk of developing foot ulcers, monthly intervention by thermography did not result in a significant reduction in ulcer recurrence rate or increased ulcer-free survival [19]. On a side note, in certain cases, foot temperature asymmetry requires the exclusion of patients with partial amputations or deformities [7].…”