Skin Tissue Water Assessed via Tissue Dielectric Constant Measurements in Persons With and Without Diabetes Mellitus

Background: Skin changes in diabetes mellitus (DM) include possible increases in foot skin water content as interpreted from altered echogenicity in high-frequency ultrasound images. The present goal was to investigate the possibility of undetected increased local skin water in persons with DM using a handheld portable rapid measuring device that measures the tissue dielectric constant (TDC) as an indicator of skin tissue water. Subjects and Methods: TDC measurements were done bilaterally on 18 persons with DM and 18 persons without DM (NODM) at foot dorsum and anterior forearm to tissue depths of 0.5, 1.5, and 2.5mm. DM duration was 11.1 +/- 10.9 years. Age, body mass index, and blood pressures were not significantly different between groups. Results: NODM and DM TDC values decreased with increasing depth at forearm but were depth independent at foot dorsum. All DM foot TDC values were significantly (P < 0.05) greater than for NODM, with foot TDC values at 2.5mm depth being 14.8% greater than in NODM. DM forearm TDC values were not significantly greater than NODM. Conclusions: A technology that characterizes local skin water in a rapid and noninvasive way has been used for the first time in persons with DM. The greater TDC value at the foot dorsum of the DM group is consistent with the presence of previously unrecognized increased fluid content. This suggests that there may be benefit utilizing this measurement method as a way to screen for early changes in foot skin features that may tend to cause DM-related edema.