Sudomotor dysfunction is associated with loss of residual renal function in patients undergoing peritoneal dialysis.

PURPOSE: Uremic neuropathy is common in dialysis patients. We investigated the association between electrochemical skin conductance (ESC), a measure of sudomotor function, and residual renal function (RRF) in patients undergoing peritoneal dialysis (PD), accounting for dialysis vintage, and examined relationships with clinical neuropathy scores. METHODS: This cross-sectional study included 86 PD patients assessed by Sudoscan and the Michigan Neuropathy Screening Instrument (MNSI), with comparison to matched stage 4-5 chronic kidney disease (CKD) patients. Absence of RRF was defined as urine output <100 mL/day or creatinine clearance <1 mL/min. Multivariable regression and moderated mediation analyses were performed. RESULTS: Hands and feet ESC decreased, while pathological ESC prevalence increased, across stage 4-5 CKD, PD with RRF, and PD without RRF (P for trend <0.001). Residual renal creatinine clearance (CCr) was independently associated with both hands and feet ESC. When CCr and dialysis vintage were entered simultaneously, CCr remained associated with feet ESC but not significantly with hands ESC. Absence of RRF was associated with pathological hands (OR 4.56, P = 0.014) and feet ESC (OR 3.70, P = 0.024). Conditional indirect associations through CCr were observed among patients without diabetes, with significant moderated mediation for feet ESC only. ESC correlated inversely with MNSI-P scores for hands (r = -0.33, P = 0.002) and feet (r = -0.31, P = 0.005). CONCLUSION: Lower RRF was associated with worse sudomotor function in PD patients, particularly for feet ESC after accounting for dialysis vintage. ESC also correlated with objective neuropathy scores. Prospective studies are needed to clarify temporal relationships.