Electrical Stimulation and Diabetic Foot Skin Perfusion

Note: The Original PI was Nancy Stotts, MAJ, USA.

This study was designed to examine the effects of electrical stimulation on the healing of foot ulcers in diabetic patients. Foot ulcers in diabetic patients are a serious problem, with a high incidence in the Black population. Delayed healing often results in infection and subsequent amputation. Electrical stimulation has been used to promote healing in patients with decubitus ulcers and venous stasis ulcers, but it had not been systematically examined in subjects with diabetic foot ulcers.

The specific aims of this repeated measures, one-group design study were to examine the effect of electrical stimulation on skin perfusion of the feet in diabetic Caucasian and Black patients who either have, or are at risk of developing foot ulcers, and assess the influence of eight moderator variables (race, gender, age, glucose control, Wagner Foot Classification, peripheral neuropathy, peripheral vascular disease, and medications) on the perfusion response to electrical stimulation.

Of the 132 subjects studied, 72 (55%) were male and 60 (45%) were female; 55 (42%) were Black and 77 (58%) were non-Black. Of the non-Black subjects, 66 were Caucasian. Ages ranged from 41 to 84 years, with a mean of 65.7 (SD 9.6). Seven subjects had insulin-dependent diabetes mellitus and 125 subjects had non-insulin dependent diabetes mellitus.

Analysis of the data demonstrated significant differences in foot skin perfusion (based on measurement of transcutaneous oxygen) before, during, and after high-voltage monophasic pulsed current. Initial foot oxygen levels (M=45.8, SD 16.27) were significantly higher than end-treatment foot oxygen levels (M=41.4, SD 21.35, p-0.02) and end-recovery foot oxygen levels (p>0.05). End-treatment foot oxygen levels were not significantly different than end-recovery foot oxygen levels. While controlling for age, ethnicity, and gender, repeated measures analysis of variance (ANOVA) showed that skin perfusion was not significantly influenced by glycohemoglobin, peripheral neuropathy, peripheral vascular disease, and Wagner Class (ulcer versus no ulcer).

Examination of the data demonstrated that there were two distinct groups of subjects: 35 subjects ("Responders") showed a significant increase in transcutaneous oxygen, and 97 subjects ("Non-Responders") showed a significant decrease in transcutaneous oxygen. Logistic regression analysis was used to distinguish Responders from Non-Responders. Results of the analysis were not statistically significant, but the following trends were identified. Subjects with any of the following characteristics were less likely to be Non-Responders: very high blood sugars, a higher level of neuropathy (insensate foot), having ulcers, and age greater than 65. Subjects with peripheral vascular disease measured by toe blood pressure less than 70mmHg, and males compared to females, were more likely to be Non-Responders. Non- Responders took nitrate- containing drugs; there was no statistical difference between subjects taking calcium channel blocking drugs and those not taking calcium-channel drugs.

No adverse effects of electrical stimulation therapy were reported. The only problem encountered was the case of one subject complaining of a tingling feeling in his hands. The symptoms were found to be unrelated to the study, and the case was reported to the organization Human Investigation Committee.

In sum, the data indicate that this treatment may provide a means to promote wound healing in individuals with diabetic neuropathy, but with adequate circulation. Since most of these groups have had diabetes for at least 15 years, this treatment would be of particular benefit to military retirees or military family members.

FINAL REPORT UNAVAILABLE