A Pilot Study of the Impact of Passive, Garment-based Infrared Therapy on Oxygenation in the Feet and Lower Legs of Patients With Diabetes

Infrared energy is a type of electromagnetic energy that is invisible, and is further subdivided into three subsets based on wavelength. Far infrared (FIR or IR-C) is a subset of energy in the infrared spectrum that is thought to transfer energy in the form of heat, perceived by thermoreceptors in the skin as radiant heat. FIR is thought to be both absorbed by the human body but is also emitted in the 3-50 micron range, with a peak output at 9.4 micron. The range of far infrared varies depending on which source is referenced but is generally felt to start at 3 to 5 microns. The use of FIR has been studied in various circumstances and thought to improve various biological functions via FIR heat lamps, saunas, ray devices and FIR emitting ceramics and fabrics. There are no short-term or long-term safety issues that have arisen in any studies thus far. As noted in the 2006 statement of the ICNIRP (International Commission on Non-Ionizing Radiation Protection), "...the contribution made by the IR-C spectral region (3-1,000 micron) is normally of no practical concern from a health hazard standpoint." FIR has been shown to increase blood flow in forearms, and access flow and survival of arteriovenous fistula in hemodialysis patients. An unpublished study, by McClue, reported an apparent increase in pedal circulation of approximately 10% using transcutaneous oxygen monitoring in healthy subjects wearing socks infiltrated with FIR emitting textiles. The mechanism of improving circulation is not entirely elucidated, however recent work suggests a role of increasing endothelial nitric oxide synthase, nitric oxide production and modulating profiles of circulating miRNAs (mircoRNA, small noncoding RNAs of ∼22nt in length which are involved in the regulation of gene expression at the posttranscriptional level).

Type 2 Diabetes prevalence has increased significantly over the past decade, with estimates from 2015 of 26 million Americans diagnosed and predicted to increase to 32 million by 2020. Both Type 1 and Type 2 Diabetes is well known to increase the risk of nontraumatic lower extremity amputation by, amongst other factors, impairing circulation to the feet through both peripheral arterial disease and microvascular dysfunction.

Noninvasive transcutaneous oximetry measurements of the leg have been validated as a valuable tool in assessing lower extremity circulation in both normal subjects and diabetic individuals.

This trial seeks to prove that exposure to IR, through the use of newly developed socks (wraps here with same material) that contain thermoreactive particles woven into textile, which both emit IR and reflect the IR back from the body, can augment circulation in the feet, arms and lower legs of diabetic subjects. Noninvasive transcutaneous oximetry will be used as the assessment modality. If this study confirms this hypothesis, future studies may be planned to determine if the use of a IR-containing textile can prevent new ulcers from forming in high risk patients and perhaps even speed the healing of prevalent foot ulcers.

Subjects will be recruited from both primary care and specialty medical offices who carry a diagnosis of Diabetes Mellitus, will be between the ages of 18 to 80 and will act as their own controls. The goal will be to enroll a minimum of one hundred (100) patients who will be evaluated noninvasively with transcutaneous oxygen measurements using Radiometer TCM (PeriFlux 5000) supplied by Radiometer America, Inc. Upon screening and after signing informed consent, patients will have ankle brachial index (ABI) measurements performed on both legs to exclude those who have severe peripheral arterial disease (ABI index or 0.4 or lower). Upon arrival on study day, subjects will have both feet evaluated by a registered nurse (RN), to ensure there are no signs of infection, active foot ulcers, or other open wounds. If there is any such evidence, the patients will be excluded from the trial and sent for further evaluation and treatment according to standard of care by their primary care clinicians or podiatrists.