Infrared Energy Therapy Not Helpful for Diabetic Neuropathy

Devices that deliver monochromatic infrared energy (MIRE) are not able to improve plantar sensation in patients with diabetic peripheral neuropathy, investigators report in Diabetes Care (2005;28:2896-2900).

Nearly one third of adults with diabetes have peripheral neuropathy. Although the management of such patients has usually involved education in foot care and routine foot assessment, physicians are increasingly using MIRE with the goal of improving lower-extremity sensation in these patients.

MIRE devices are approved by the FDA to increase circulation and reduce pain, and recent case reports and uncontrolled studies have supported their use for reversing lower-extremity sensory neuropathy, the investigators noted.

Judy K. Clifft, PT, MS, of the University of Tennessee Health Science Center, Memphis, and colleagues randomized 39 patients with diabetic peripheral neuropathy to 30 minutes of active or placebo MIRE, applied 3 times weekly for 4 weeks. The goal was to test the immediate and long-term benefits of MIRE therapy in this patient population.

Plantar sensation was tested with monofilaments at the start of the trial, after 4 weeks of treatment, and after an additional 4 weeks without treatment.

The investigators had hypothesized that the mean number of sites on the plantar surface of the foot where patients could sense a 5.07 monofilament would be significantly greater in the active than in the placebo MIRE groups. The 5.07 monofilament is frequently used by physicians to identify loss of protective sensation. It is also a sensitive tool for determining which patients are at increased risk of developing foot ulcers.

However, their hypothesis was not borne out by the results. "In this study, we found no significant differences between active and placebo MIRE in improving plantar sensation in patients with diabetic peripheral neuropathy," the investigators wrote. In fact, no significant differences between active and placebo groups were documented at any test site.

The authors emphasize that the MIRE device "would have appeared to be therapeutically effective" if their study design had not used a placebo control. They added that future studies "should be only double-blind and placebo-controlled with adequate sample size to determine whether active MIRE is any more effective than placebo MIRE."

Research is also needed to study the effects of longer treatment times, different pad placements, and the use of other assessment techniques.?J.S.