Effects of Intradialytic Neuromuscular Electrical Stimulation Versus Resistance Exercise on Physical Function, Dialysis Adequacy, and Fatigue in Patients Receiving Maintenance Hemodialysis: A Randomized Controlled Trial

Background: Patients receiving maintenance hemodialysis commonly experience reduced lower-limb muscle strength, impaired walking capacity, fatigue, and reduced physical function. Intradialytic resistance training and neuromuscular electrical stimulation (NMES) are practical rehabilitation strategies, but direct comparisons between these interventions remain limited. Objective: To compare the effects of intradialytic NMES, intradialytic resistance training, and usual care on dialysis adequacy, lower-limb muscle strength, functional walking capacity, estimated peak oxygen uptake, and physical fatigue in patients receiving maintenance hemodialysis. Methods: This three-arm randomized controlled trial included 90 patients receiving maintenance hemodialysis. Participants were allocated equally to an intradialytic NMES group, an intradialytic resistance-training group, or a usual-care control group. Both active interventions were delivered twice weekly during the first 2 hours of hemodialysis for 16 weeks. Outcomes were assessed at baseline and after the intervention and included urea reduction ratio (URR), bilateral quadriceps and plantar-flexor strength, six-minute walk distance (6MWD), estimated peak oxygen uptake calculated from 6MWD, and physical fatigue. Within-group changes were summarized using paired analyses. Between-group treatment effects were estimated using baseline-adjusted analysis of covariance (ANCOVA) and reported as adjusted mean differences with 95% confidence intervals. Results: Both intradialytic NMES and resistance training produced significant baseline-adjusted improvements in URR, bilateral lower-limb muscle strength, 6MWD, estimated peak oxygen uptake, and physical-fatigue scores compared with usual care (all adjusted p<0.001). No statistically significant adjusted differences were observed between the two active interventions for lower-limb strength, 6MWD, estimated peak oxygen uptake, or physical fatigue (all adjusted p ≥ 0.12); because the trial was not designed as a non-inferiority study, this should not be interpreted as evidence of equivalence. Resistance training produced a significantly higher adjusted post-intervention URR than NMES (adjusted MD 4.12 percentage points, 95% CI 3.21 to 5.02, p<0.001). Conclusion: Intradialytic NMES and resistance training were both associated with improved URR, lower-limb muscle performance, functional walking capacity, calculated estimated peak oxygen uptake (a derived measure of 6MWD), and physical fatigue in patients receiving maintenance hemodialysis, relative to usual care. No statistically significant difference was detected between NMES and resistance training for these outcomes other than URR; because the trial was not designed to test non-inferiority, this finding should not be interpreted as demonstrating equivalence between the two interventions. NMES may provide a practical, hypothesis-generating rehabilitation alternative for patients who cannot undertake voluntary resistance training.