Evaluation of Real-World Smart Sock-Based Temperature Monitoring Data as a Physiological Indicator of Early Diabetic Foot Injury: Case-Control Study (Preprint)
BACKGROUND Diabetic foot ulcers represent major health care complications both in terms of cost and impact to quality of life for patients with diabetic peripheral neuropathy. Temperature monitoring has been shown in previous studies to provide a useful signal of inflammation that may indicate the early presence of a foot injury. OBJECTIVE In this study we evaluated the temperature data for patients that presented with a diabetic foot injury while utilizing a sock-based remote temperature monitoring device. METHODS The study abstracted data from patients enrolled in a remote temperature monitoring program in year 2020-2021 using a smart sock (Siren Care, San Francisco, California, USA). In the study cohort, a total of 5 participants with a diabetes-related lower extremity injury during study period were identified. In the second comparison cohort, a total of 26 patients met the criteria for monitoring by the same methods that did not present with a diabetes-related podiatric injury during the same period. The 15-day temperature differential between six defined locations on each foot was the primary outcome measure among subjects who presented a diagnosed foot injury. Paired t-tests were used to compare the differences between the two groups. RESULTS A significant difference in temperature differential was observed in the group that presented with a podiatric injury over the course of evaluation vs. the comparator group that did not present with a podiatric injury with temperature measured in °F. The average difference from all six measured points was 1.4°F between the injury group (mean 3.6 +/- 3.0) and the comparator group (mean 2.2 +/- 2.5, t=-71.4; P<.000). CONCLUSIONS The presented study demonstrated significant temperature difference for patients presenting with a foot injury in a 15-day period prior to the diagnosis of an injury compared with a similar period for patients without an injury. The findings suggest temperature monitoring may be a predictor of a developing foot injury. The continuous temperature monitoring system employed has implications for further algorithm development to enable early detection. The study was limited by a nonrandomized, observational design with limited injuries present in the study period.