Foot ulcers remain the most common reason for hospital admission among veterans with diabetes. Healing and preventing these wounds should be a high priority for clinicians treating these high-risk patients. Previous work by the investigators has suggested that diabetic foot ulcers are preceded by inflammation, which can potentially be detected with a thermometer.
The purpose of this project is to evaluate the utility of a novel personal dermal thermometry system to empower patients and caregivers and thereby reduce the risk for lower extremity ulceration and amputation in veterans at high risk for these complications.
In this randomized clinical trial, 384 patients are being enrolled and assigned to either standard of care (SC) or SC plus a personal dermal thermometer (DT) to evaluate and log their plantar skin temperatures. All patients are given access to a 24 hour "hot foot line" to call for immediate access to care if they identify a hot spot (DT group) or a site of concern on standard self-evaluation (SC). All patients are assigned a sophisticated computerized activity monitor, which allows investigators access to time and magnitude of activity, downloaded at regular patient visits.
One major manuscript has been produced from the preliminary data (Armstrong, et al, Diabetes Care, 2004): Purpose: to evaluate the role of activity in development of neuropathic foot ulceration in persons with diabetes.
Methods: We evaluated the first 100 consecutive persons with diabetes, (95.0% male, aged 68.5 ± 10.0 years and concomitant neuropathy, deformity and/or a history of lower extremity ulceration/partial foot amputation) enrolled in an ongoing prospective longitudinal activity study. Subjects used a high-capacity continuous computerized activity monitor. Data were collected continuously over a minimum of 25 weeks (or until ulceration) with daily activity units expressed as mean ± standard deviation.
Results: Eight subjects ulcerated during the evaluation period of 37.1 ± 12.3 weeks. Average daily activity was significantly lower in persons that ulcerated (U) compared to persons that did not ulcerate (NU) (809.0 ± 612.2 vs. 1394.5 ± 868.5, p = 0.03). Furthermore, there was a large difference in variability between groups. The coefficient of variation (CoV) was significantly greater in the U group compared with the NU (96.4 ± 50.3% vs. 44.7 ± 15.4%, p=0.0001). In the two weeks preceding the ulcerative event, the CoV increased even further (115.4 ± 43.0%, p = 0.02) but there was not a significant difference in average daily activity during that period (p = 0.5).
Conclusions: The results of this study suggest that persons with diabetes who develop ulceration may actually have a lower overall activity than their NU counterparts but the quality of that activity may be more variable. Perhaps modulating the “peaks and valleys” of activity in this population through some form of feedback might prove to reduce risk for ulceration in this very high risk population.
We plan on publishing results based on the thermometry intervention following conclusion of the follow-up period.
If dermal thermometry proves to be a useful "early warning system", we anticipate potential widespread implementation of this very simple tool to identify sites of impending ulceration, thereby reducing the unconscionably high rate of ulceration and amputation in veterans with diabetes.
Secondary analysis of activity data has proven to be unexpectedly beneficial. We are now concluding that activity monitoring and modulation may be as important as monitoring for inflammation (temperature) in the prediction (and ultimate prevention) of wounds
- Armstrong DG, Lavery LA, Holtz-Neiderer K, Mohler MJ, Wendel CS, Nixon BP, Boulton AJ. Variability in activity may precede diabetic foot ulceration. Diabetes Care. 2004 Aug 1; 27(8):1980-4.