Effects of intradialytic cycling exercise on exercise capacity, quality of life, physical function and cardiovascular measures in adult haemodialysis patients: a systematic review and meta-analysis

Background: Intradialytic cycling (IDC), delivered during haemodialysis (HD) has the potential to improve many health issues. This systematic review and meta-analysis examines the evidence on the effects of IDC on exercise capacity, quality of life (QOL), physical function & cardiovascular health. Methods: Twenty-four databases were searched alongside internet, hand searching and consultation with experts. Eligibility criteria were cluster randomised, randomised and quasi randomised controlled trials (RCTs) of IDC versus usual care in prevalent adult HD patients. Primary outcome measures were exercise capacity (VO2 peak and field tests) and QoL. Secondary measures were cardiac and physical function. Results: Thirteen RCTs were eligible. Eight provided data for use in meta-analyses, which indicated no significant change in VO2 peak (MD 1.19 ml/kg/min , 95% confidence interval - 1.15 to 3.52, p=0.3), physical (MC 1.97, 95% CI –8.27 to 12.22, p=0.7) or mental component (MC 3.37, 95% CI -7.94 to 14.68, p=0.6) summary scores of the Medical Outcomes Short Form 36, pulse wave velocity (MD -0.57m/s, -1.55 to 0.41, p=0.4), systolic (MD - 2.28mmHg, -14.46 to 9.90, p=0.7) or diastolic blood pressure (MD 2.25mmHg, -3.01 to 7.50, p=0.4) following IDC. IDC, however, leads to an improvement in performance on the six minute walk test (MD 87.84m 39.60 to 136.09, p=0.0004). All included studies were considered to have high risk of bias. Conclusions. There is insufficient evidence demonstrating that cycling exercise during HD improves patient outcomes. High quality, adequately powered, RCTs of IDC are required