[Sweat function evaluation for early diagnosis of diabetic peripheral neuropathy]

To evaluate the clinical value of sweat function examination in early diagnosis of diabetic peripheral neuropathy (DPN).

Ninety-eight hospitalized type 2 diabetic patients with or without DPN (DN and DC groups) according to Michigan Diabetic Neruopathy Score (DNS) and 40 healthy volunteers (NC group) were evaluated for their sweat function of the feet in relation to the peripheral autonomic nerve with sweat printing method using Neuropad. The Neuropad color-changing time was recorded to assess the sensitivity and specificity of sweat printing methods relative to DNS for DNP evaluation, and the correlation of the Neuropad color-changing time to DNS score was analyzed.

The average Neuropad color-changing time was 4.0-/+0.6, 4.3-/+1.2 and 23.0-/+6.1 min in NC, DC, and DN groups, respectively, showing significant differences between the 3 groups (P<0.05). The morbidity rate detected by sweat printing method was 62.2%, similar to that detected by DNS (57.1%, P>0.05). The sensitivity of the sweat printing method for DPN diagnosis was 92.8%, with specificity of 78.5%, positive predictive value of 93.2%, and negative predictive value of 78.6%. DNS showed significant positive correlation with the Neuropad color-changing time (r=0.46, P<0.05).

Sweat printing method provides an objective, simple and reliable method for sweat function evaluation of the feet of type 2 diabetic patients to help in early DPN diagnosis, and quantification of the results of sweat printing method can be indicative of the DPN severity.