Patients with diabetic neuropathy who monitor their foot temperature daily can reduce their risk of ulceration more than fourfold, according to an article by Lawrence A. Lavery, D.P.M., of Texas A&M University, College Station, and colleagues.
In a physician-blinded trial, 173 patients with a previous history of diabetic foot ulceration were randomly assigned to one of three groups: standard therapy, structured foot examination, or enhanced therapy (Diabetes Care 2007;30:14–20).
Patients who were assigned to standard therapy received a therapeutic insoles and footwear, participated in an educational program focused on foot complications and self-care, and had a lower extremity evaluation by a physician every 8 weeks. Those assigned to the structured foot examination group received the standard therapy as well as training to conduct a detailed self-examination with the assistance of a mirror to identify redness, discoloration, swelling, and local warmth.
The patients in the enhanced therapy group also received the standard therapy and in addition, were taught to use a digital infrared thermometer to measure and record daily temperatures at six sites on each foot.
Of the 59 patients in the enhanced therapy group, 5 experienced ulceration over the 15-month treatment period, compared with 17 of the 58 patients in the standard group and 17 of the 56 patients in the structured foot examination group, a significant difference. The mean time to ulcerate was 378.5 days in the standard therapy group, 377.3 days in the structured foot examination group, and 429.5 days in the enhanced therapy group. The enhanced therapy group was significantly better than each of the other two groups, and those two groups did not differ from each other.
Patients in the enhanced therapy group were 4.48 times less likely to develop foot ulceration than those in the standard therapy group and 4.71 times less likely to develop foot ulceration than those in the structured foot examination group.
Within the enhanced therapy group, patients who were compliant with recording foot temperatures at least 50% of the time were 50 times less likely to develop an ulcer than were patients who were not compliant. Four of the five foot ulcers were in patients who were not compliant.
Patients in the enhanced therapy group were taught to monitor temperatures on the great toe, the first, third, and fifth metatarsal head region, the midfoot, and the heel of each foot using a TempTouch digital infrared thermometer, available by prescription from Xilas Medical, San Antonio. They were instructed to contact the research nurse if skin temperatures were elevated by more than 4° F (2.2° C), compared with the corresponding side on the opposite foot for 2 consecutive days. They were also instructed to decrease their activity until temperatures normalized.
About 88% of the patients in the enhanced therapy group were compliant with daily temperature measurements. This compares quite favorably with published rates of compliance with daily glucose monitoring, which can be as low as 33%.
“It seems likely that the cost benefit of home temperature monitoring might be much better than that for use in glucose strips for home monitoring,” the investigators wrote. “In addition, a tool to adjust activity could help with the dilemma of exercising for better health versus the need to rest and protect the foot to avoid foot ulcers.”
Several of the study's authors disclosed close relationships with Xilas Medical. Dr. Lavery owns stock in the company, and is a consultant and a member of its clinical advisory board. Two of the other authors are members of the company's board of directors. The study was supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases.