Effect of intradialytic exercise on cardiovascular structural and functional parameters in maintenance haemodialysis: a systematic review and meta-analysis.

To evaluate the impact of intradialytic exercise (IDE) on cardiovascular structural and functional parameters in patients receiving maintenance haemodialysis (MHD). A systematic review and meta-analysis. PubMed, Embase, Web of Science and the Cochrane Central Register of Controlled Trials were searched from inception through January 2026. Randomised controlled trials (RCTs) involving adults receiving MHD who underwent structured IDE versus usual care or non-exercise controls and reported cardiac, vascular or cardiorespiratory outcomes. Two independent reviewers performed literature screening, data extraction and outcome-level risk of bias assessment using the Cochrane Risk of Bias 2 (RoB 2) tool. Random-effects models were used to pool mean differences (MDs) and 95% CIs. Certainty of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Fourteen studies involving 934 participants were included. IDE increased left ventricular end-diastolic volume (3 studies, 213 participants; MD 14.15 mL, 95% CI 2.06 to 26.24; p=0.022), improved left ventricular ejection fraction (LVEF) (6 studies, 396 participants; MD 2.21%, 95% CI 0.28 to 4.15; p=0.025), reduced pulse wave velocity (PWV) (4 studies, 211 participants; MD -1.36 m/s, 95% CI -2.58 to -0.13; p=0.031) and increased peak oxygen uptake (Peak VO2) modestly (6 studies, 583 participants; MD 2.76 mL/kg/min, 95% CI 0.08 to 5.43; p=0.044). Diastolic blood pressure (DBP) was reduced (4 studies, 221 participants; MD -4.54 mm Hg, 95% CI -7.57 to -1.51; p=0.003). No significant differences were observed for left ventricular mass index (LVMI) (5 studies, 258 participants; MD -1.19 g/m², 95% CI -5.63 to 3.24; p=0.597) or systolic blood pressure (SBP) (4 studies, 221 participants; MD -8.76 mm Hg, 95% CI -20.38 to 2.86; p=0.139). Outcome-level risk-of-bias assessments predominantly showed some concerns, with high risk identified for individual contributing results. Heterogeneity was substantial for Peak VO2 (I²=90.07%) and SBP (I²=73.20%). Certainty of evidence was moderate for LVMI, LVEF, PWV and DBP and low for the remaining outcomes. IDE may improve cardiovascular function, arterial stiffness and cardiorespiratory fitness in patients receiving MHD. Effects on LVMI and SBP remain uncertain. Certainty of evidence ranged from moderate to low, and risk-of-bias concerns and substantial heterogeneity for some outcomes warrant cautious interpretation. CRD420261336421.