Electrochemical Skin Conductance by Sudoscan in Non-Dialysis Chronic Kidney Disease Patients

Background. Peripheral neuropathy is prevalent among patients with chronic kidney disease (CKD). Sudoscan non-invasively detects polyneuropathy by measuring electrochemical skin conductance (ESC). We conducted a study on sudomotor function in CKD patients across various stages based on their estimated glomerular filtration rate (eGFR). Methods. In this cross-sectional study of 700 CKD patients, all underwent Sudoscan. Pathological ESC was defined as hands < 40 μS or feet < 50 μS. Clinical neuropathy scores including Michigan Neuropathy Screening Instrument (MNSI) and Douleur Neuropathique en 4 questionnaire (DN4) were obtained. Results. Among participants, 344 had diabetes and 356 did not. Hands and feet ESC decreased with CKD progression (median (IQR) in stage 1–2, 3, 4–5: 54.0 (39.0–68.0), 45.5 (30.0–63.0), 41.8 (26.5–60.5), p trend < 0.001; 64.5 (53.5–74.0), 60.5 (43.0–72.5), 55.0 (39.0–69.8), p trend < 0.001). Pathological hands and feet ESC increased in later CKD stages (stage 1–2, 3, 4–5: 26.6%, 40.9%, 45.7%, p trend < 0.001; 21.7%, 34.0%, 40.6%, p trend < 0.001). Positive hands and feet ESC-eGFR correlation existed irrespective of diabetes. Diabetic patients had lower hands and feet ESC than non-diabetics as CKD progressed. However, multivariate regression found no significant ESC-eGFR association. Sudoscan correlated with clinical neuropathy scores. Conclusion. Pathological sudomotor function was common in non-dialysis CKD stages 4–5. Diabetic patients had worse function. Sudomotor dysfunction progressed with renal disease but eGFR was not an independent risk factor.