Unilateral remote temperature monitoring to predict future ulceration for the diabetic foot in remission

Abstract

ObjectiveDaily remote foot temperature monitoring is an evidence-based preventive practice for patients at risk for diabetic foot complications. Unfortunately, the conventional approach requires comparison of temperatures between contralaterally matched anatomy, limiting practice in high-risk cohorts such as patients with a wound to one foot and those with proximal lower extremity amputation (LEA). We developed and assessed a novel approach for monitoring of a single foot for the prevention and early detection of diabetic foot complications. The purpose of this study was to assess the sensitivity, specificity, and lead time associated with unilateral diabetic foot temperature monitoring.Research design and methodsWe used comparisons among ipsilateral foot temperatures and between foot temperatures and ambient temperature as a marker of inflammation. We analyzed data collected from a 129-participant longitudinal study to evaluate the predictive accuracy of our approach. To evaluate classification accuracy, we constructed a receiver operator characteristic curve and reported sensitivity, specificity, and lead time for four different monitoring settings.ResultsUsing this approach, monitoring a single foot was found to predict 91% of impending non-acute plantar foot ulcers on average 41 days before clinical presentation with a resultant mean 4.2 alerts per participant-year. By adjusting the threshold temperature setting, the specificity could be increased to 78% with corresponding reduced sensitivity of 53%, lead time of 33 days, and 2.2 alerts per participant-year.ConclusionsGiven the high incidence of subsequent diabetic foot complications to the sound foot in patients with a history of proximal LEA and patients being treated for a wound, practice of daily temperature monitoring of a single foot has the potential to significantly improve outcomes and reduce resource utilization in this challenging high-risk population.

Development of a Model to Predict Healing of Chronic Wounds Within 12 Weeks

“…41 Similarly, measures of metabolic control, like HbA 1c , ankle brachial index for perfusion or skin temperature for inflammation are correlated with wound healing but not yet documented routinely in our data. 25,36,42 Conversely, we have no evidence that increasing the complexity of the model structure will raise predictive accuracy. We tested several interaction effects with only marginal improvement in the AUC.…”

Accuracy of a foot temperature monitoring mat for predicting diabetic foot ulcers in patients with recent wounds or partial foot amputation

“…Ideally, practice should begin during treatment to prepare and set expectations for the patient as well as to establish daily routines to maximize adherence to the monitoring regimen post-healing. Fortunately, investigators have recently published a unilateral foot temperature monitoring protocol for the mat that allows patients being treated for a wound on one foot to monitor the unwounded foot [13]. While previous foot temperature monitoring protocols required two feet for contralateral comparison, this new approach requires only one foot, allowing foot temperature monitoring to begin during treatment.…”

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

“…Prior research suggests that a temperature difference between identical sites on opposite feet of >2.2 • C (equivalent to~4 • F) on two consecutive days can accurately predict ulcer development [21,22]. It has recently been reported that the difference between the median of temperature at six key locations on one foot (the hallux, first, third and fifth metatarsal heads, the mid-foot and heel) and ambient temperature is also able to predict foot ulcer development with an excellent sensitivity, although with limited specificity [23]. This potentially allows people with a unilateral foot ulcer and those with prior unilateral major amputation to also be monitored for the hot spots that are predictive of impending ulcers.…”

“…The previous trials testing home foot temperature monitoring [17][18][19] have excluded people with peripheral artery disease (PAD), which is an established risk factor for foot ulceration, thereby limiting the generalizability [20][21][22]. Both PAD and DPN have been reported to influence foot temperature [23]. In a recent thermal imaging study, participants with PAD had a significantly higher foot temperature than those that did not have PAD [26,27].…”

“…The most advanced, currently described system for the automated measurement of foot temperature is the Podimetrics Mat [23,30]. This is a wireless mat that is designed to remotely monitor the temperature of the plantar surface of the foot with minimal involvement from the patient [30].…”