Temperature as a Causative Factor in Diabetic Foot Ulcers: A Call to Revisit Ulceration Pathomechanics

Abstract

Background: Diabetic foot ulcers (DFUs) are a major burden to patients and to the health-care systems of many countries. To prevent or treat ulcers more effectively, predictive biomarkers are needed. We examined temperature as a biomarker and as a causative factor in ulcer development. Methods: Thirty-seven individuals with diabetes were enrolled in this observational case-control study: nine with diabetic neuropathy and ulcer history (DFU), 14 with diabetic neuropathy (DN), and 14 nonneuropathic control participants (DC). Resting barefoot plantar temperatures were recorded using an infrared thermal camera. Mean temperatures were determined in four anatomical regions—hallux and medial, central, and lateral forefoot—and separate linear models with specified contrasts among the DFU, DN, and DC groups were set to reveal mean differences for each foot region while controlling for group characteristics. Results: The mean temperature reading in each foot region was higher than 30.0°C in the DFU and DN groups and lower than 30.0°C in the DC group. Mean differences were greatest between the DFU and DC groups, ranging from 3.2°C in the medial forefoot to 4.9°C in the hallux. Conclusions: Increased plantar temperatures in individuals with a history of ulcers may include acute temperature increases from plantar stresses, chronic inflammation from prolonged stresses, and impairment in temperature regulation from autonomic neuropathy. Diabetic foot temperatures, particularly in patients with previous ulcers, may easily reach hazard thresholds indicated by previous pressure ulcer studies. The results necessitate further exploration of temperature in the diabetic foot and how it may contribute to ulceration.