September 2019

Unilateral remote daily temperature monitoring to predict diabetic foot ulcers shows promise

Figure 1. The technology used in this study was a remote temperature monitoring foot mat certified as a “high-traction” product by the National Floor Safety Institute and legally marketed in the USA as a class I medical device. Photo is courtesy of the manufacturer, Podimetrics, Somerville, Massachusetts.

By Lynn Soban, PhD, MPH, RN

Diabetic foot ulcers (DFUs), the primary antecedent to diabetes-related lower extremity amputation (LEA), are common, costly, and preventable. Following a period of decline in incidence, the Centers for Disease Control and Prevention found the occurrence of diabetes-related LEA had rebounded an alarming 50% percent between 2009 and 2015. This troubling trend is a reminder of the need for diligent attention and innovation in the area of DFU prevention.

Prevention of DFUs is possible: Indeed, a 2016 study by Bus and van Netten showed that 75% of DFUs are preventable with the routine provision of comprehensive preventive foot care.

Once daily remote foot temperature monitoring is an effective, recommended, and emerging practice for reducing incidence of DFU. This type of monitoring is able to spot potential inflammation that, left unchecked, can lead to DFU, infection, or even acute Charcot neuroarthropathy. Prior research found that use of a smart mat with specialized sensors to assess asymmetry in foot skin temperatures demonstrated 97% sensitivity to detect all non-acute plantar DFUs an average of 35 days before clinical presentation. Such early warning would allow a patient’s care team the opportunity to intervene earlier than normally possible.

Unfortunately, many at-risk patients are unable to measure temperatures on both feet due to a history of high-level amputation or ongoing treatment of an unhealed wound. DFUs are likely to recur in anatomical locations distinct from the primary location; patients being treated for a wound and those who experienced a LEA are at an elevated risk for diabetes-related complications to the sound foot.

Data from: Örneholm H, Apelqvist J, Larsson J, et al. Recurrent and other new foot ulcers after healed plantar forefoot diabetic ulcer. Wound Rep and Reg 2017;25:309–15.

Now, a new study, published in BMJ Open Diabetes Research & Care, examined the predictive ability of this technology for patients with only one foot available for evaluation.  Researchers performed secondary analysis of data from a 129-participant study of individuals with a history of both diabetes mellitus and a previously-healed plantar DFU; participants were followed for a maximum of 34 weeks. The study device was a daily remote temperature monitoring foot mat (Remote Temperature Monitoring System; Podimetrics, Somerville, MA, USA). Analysis examined temperatures and outcomes of single feet to assess sensitivity, specificity, and lead time associated with unilateral diabetic foot temperature monitoring.

Results of this analysis were very encouraging: monitoring a single foot was found to predict 91% of impending non-acute plantar foot ulcers an average of 41 days before clinical presentation with a specificity of 46%. Given the high incidence of subsequent diabetic foot complications in patients with a history of proximal LEA and those being treated for a wound, use of daily temperature monitoring in these populations has the potential to significantly reduce morbidity, mortality, and resource utilization related to DFU. Future research using primary data would allow independent validation of these very promising findings.

Lynn Soban, PhD, MPH, RN, is a health services researcher and implementation scientist with expertise in quality improvement related to pressure ulcer prevention.  She lives in Santa Monica, California.

Source: Lavery LA, Petersen BJ, Linders DR et al. Unilateral remote temperature monitoring to predict future ulceration for the diabetic foot in remission. BMJ Open Diab Res Care 2019; 7: e000696.

See also: Frykberg RG, Gordon IL, Reyzelman AM, et al. Feasibility and efficacy of a smart mat technology to predict development of diabetic plantar ulcers. Diabetes Care 2017;40:973–80.

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