The utility of skin surface temperature measurement in the prediction of diabetic foot ulceration

Abstract

Aim

Temperature is a marker of inflammation. Research has shown that by measuring skin surface temperature in those with a history of diabetic foot ulceration (DFU), tissue damage can be identified early and reduce rates of subsequent DFU. This study considered whether measuring skin surface temperature using infra-red thermometry can identify early tissue damage and inform clinical practice in a general population with Diabetes Mellitus (DM).

Method

The data presented was taken from a prospective observational study of risk factors in patients with Diabetes. As part of this study, temperature measurements using the Flir E6 Infra-red camera were taken from 216 individuals attending outpatient diabetes clinics in a large urban teaching hospital in Ireland as part of a comprehensive diabetic foot assessment. Measurements were taken at foot sites associated with increased risk at baseline received repeat temperature measurement on 2 subsequent occasions in the following week. Any ulceration was subsequently recorded.

Results

Discussion: Of the 216 participants, 4 % (n = 9) developed visual ulceration within 7 days. All of these had been identified at high risk at baseline assessment and had a history of foot disease. A temperature differential of ≥2.2 °C between sites of interest was recorded. Temperature ranges varied from 29.1 °C to 37.6 °C. High temperature was considered if over 35 °C. Of those who developed a diabetic foot ulceration within the 7 day follow up period, 78 % (n = 7) had a high temperature. The remaining 22 % (n = 2) who developed ulceration had a temperature reading in the normal range.

Conclusion

Elevated skin surface temperature was seen prior to the development of DFU in all cases in this study. Initial analysis suggests that neither the 35 °C threshold nor a 2.2 °C temperature difference is indicative of inevitable tissue damage in this population due to the high number of false positives seen.