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

BACKGROUND: Diabetic foot ulcers are a major burden to patients and to the healthcare systems of many countries. To prevent and/or treat ulcers more effectively, predictive biomarkers are needed. We examined temperature as a biomarker and as a causative factor in ulcer development.

METHODS: 37 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 non-neuropathic participants (DC). Resting barefoot plantar temperatures were recorded using an infrared thermal camera. Mean temperature in each region was determined based on 4 anatomical regions; hallux, medial forefoot, central forefoot, and lateral forefoot and separate linear models with specified contrasts between DFU, DN, and DC groups were set to reveal mean differences for each foot region, while controlling for group characteristics.

RESULTS: Mean temperature readings in each foot region was higher than 30.0°C in the DFU and DN compared to the DC group with all temperatures below 30.0°C. Mean differences were greatest between the DFU and the DC group, with mean differences 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 those with previous ulcers, may easily reach hazard thresholds indicated by prior pressure ulcer studies. The results necessitate further exploration of temperature in diabetic foot and how it may contribute to ulceration.