Neuropad Assessment of Sudomotor Function Across Glycemic Levels in Adults

To evaluate the impact of metabolic indicators on plantar sudomotor function and to explore the relationships between metabolic and non-metabolic indicators and sudomotor function in a physical examination cohort using Neuropad.

In this cross-sectional study, 481 participants were randomly enrolled. Sudomotor function was evaluated using Neuropad and a handheld color analyzer for both qualitative (visual Neuropad) and quantitative (quantitative Neuropad) analyses. The slope (Slope[1-10]) was used as a quantitative measure of sudomotor function.

Additional data included age, BMI (body mass index), FPG (fasting plasma glucose), HbA1c (hemoglobin A1c), blood pressure, lipid levels, and liver and kidney function. Participants were categorized into four blood glucose groups: normoglycemia (FPG <6.1 mmol/L and HbA1c <6%), prediabetes (FPG 6.1-6.9 mmol/L or HbA1c 6.0-6.4%), newly diagnosed diabetes (FPG ≥7.0 mmol/L or HbA1c ≥6.5% with no prior diagnosis, diabetes was diagnosed on the day of the physical examination), and previously diagnosed diabetes.

(1) The previously diagnosed diabetes group presented a lower slope than the normoglycemia group (6.96 vs 8.73) and a greater rate of incomplete color change (71.11% vs 49.01%). With increasing FPG and HbA1c levels, the 10-minute slope decreased progressively (P =0.003, P=0.006). (2) A multivariable linear mixed-effects model adjusted for confounders indicated that previously diagnosed diabetes was an independent predictor of reduced sudomotor function. (3) Adjusting for the same confounders, previously diagnosed diabetes was associated with a 3.480-fold greater risk of incomplete color change than was normoglycemia (OR = 3.480, 95% CI = 1.506-8.042). (4) Age, BMI, ALB, eGFR, and alcohol consumption history were closely associated with sudomotor function.

There is a progressive decline in sudomotor function with increasing blood glucose levels in a physical examination cohort, and previously diagnosed diabetes emerges as an independent risk factor for sudomotor dysfunction.