Abstract
Rationale
Loss of skeletal muscle mass and function is a common, debilitating complication of kidney failure for individuals undergoing dialysis. It contributes to reduced physical capacity, quality of life (QoL), and increased death. Exercise training can mitigate these effects, but participation is often limited by comorbidities, fatigue, and logistical constraints of dialysis treatment. Neuromuscular electrical stimulation (NMES) offers a potential alternative or adjunct to exercise by inducing muscle contractions through surface electrodes. Despite increasing research interest, the evidence for its effectiveness and safety in adults with kidney failure undergoing dialysis remains uncertain. This review systematically evaluates the effects of lower-limb NMES training programmes on muscle structure and function, physical performance, cardiovascular outcomes, and biochemical markers in adults receiving dialysis.Objectives
The aim of this review was to assess the effects of NMES, compared with no NMES, on critical and important outcomes in adults with kidney failure receiving dialysis. The objectives were to evaluate the effect of NMES on critical outcomes, including life participation, fatigue, cardiovascular outcomes, pain, infection, death, and vascular access problems, and on important outcomes, including muscle function, functional performance, muscle structure, QoL, mechanisms, and treatment experience.Search methods
The Cochrane Kidney and Transplant Information Specialist conducted comprehensive searches in CENTRAL, MEDLINE, Embase, and trial registries, including ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform. Searches had no restrictions on language, publication date, or status (search date 16 June 2025). We hand-searched the reference lists of included studies and relevant reviews to identify additional studies.Eligibility criteria
We included randomised controlled trials (RCTs) and cluster RCTs evaluating lower-limb NMES interventions delivered via surface electrodes in adults (≥ 18 years) with kidney failure receiving haemodialysis or peritoneal dialysis. Eligible comparators included usual care, sham NMES, or exercise (where a usual care control was also present). We excluded studies using single-session NMES or NMES in transient acute dialysis samples, combining NMES with concurrent exercise without a control group, or conducted in non-dialysis chronic kidney disease populations. We contacted authors to obtain missing data when necessary.Outcomes
Critical outcomes included life participation, cardiovascular outcomes (blood pressure and resting heart rate), death, fatigue, pain, infection, and vascular access problems. Important outcomes included muscle function, functional performance, muscle structure, QoL, biochemical or hormonal markers related to muscle metabolism and inflammation, and treatment experience. The synthesis of results presented in this abstract focuses on the critical outcomes.Risk of bias
Risk of bias was assessed using the Cochrane RoB 2 tool.Synthesis methods
We analysed the data using a random-effects model. Continuous outcomes were expressed as mean difference (MD) or standardised mean difference (SMD), and dichotomous outcomes as risk ratios (RRs), with 95% confidence intervals (CIs). We assessed heterogeneity using the I² statistic and explored it narratively where pooling was inappropriate. When meta-analysis was not possible, we summarised results following Synthesis Without Meta-analysis (SWiM) guidance. We assessed the certainty of evidence for each outcome using GRADE methodology.Included studies
Twelve RCTs, published between 2011 and 2025, met our inclusion criteria. Across all study arms, 439 participants were randomised, of whom 348 were randomised to NMES or control groups eligible for inclusion in this review. After participant withdrawals and missing outcome data were accounted for, 299 participants contributed to one or more meta-analyses. Studies were conducted in haemodialysis centres or units across eight countries. Intervention durations ranged from four to 20 weeks. NMES parameters varied widely: stimulation frequencies ranged from 5 Hz to 100 Hz, session durations from 20 to 60 minutes, and treatment frequencies from two to five sessions per week.Synthesis of results
The certainty of the evidence ranged from very low to low and was commonly downgraded because of the risk of bias and imprecision associated with small sample sizes. The evidence is very uncertain about the effect of NMES on life participation (MD 1.00, 95% CI -3.85 to 5.85; I² not applicable; 1 study, 20 participants; very low-certainty evidence). NMES may result in little to no difference in diastolic blood pressure (MD 2.72, 95% CI -2.85 to 8.29; I² = 0%; 4 studies, 101 participants; low-certainty evidence). NMES may result in little to no difference in systolic blood pressure (MD 5.54, 95% CI -4.02 to 15.09; I² = 0%; 4 studies, 101 participants; low-certainty evidence). NMES may result in little to no difference in resting heart rate (MD 4.58, 95% CI -2.67 to 11.82; I² = 0%; 2 studies, 55 participants; low-certainty evidence). The evidence is very uncertain about the effect of NMES on death (RR 0.24, 95% CI 0.01 to 5.26; I² not applicable; 1 study, 22 participants; very low-certainty evidence). No studies reported fatigue, pain, infection, or vascular access problems. None of the studies included adults undergoing peritoneal dialysis.Authors' conclusions
The evidence is very uncertain about the effects of NMES on life participation and death in adults with kidney failure receiving haemodialysis. Low-certainty evidence suggests NMES may result in little to no difference in blood pressure or resting heart rate. No studies reported fatigue, pain, infection, or vascular access problems. The available evidence is limited by small sample sizes, methodological limitations, and imprecision, highlighting the need for larger, high-quality RCTs evaluating patient-centred outcomes.Funding
This Cochrane Review had no dedicated funding.Registration
Protocol (2025) DOI: 10.1002/14651858.CD016155.