Effects of exercise training on frailty, cardiorespiratory fitness, and lower limb function in non-dialysis chronic kidney disease: a systematic review and meta-analysis.

INTRODUCTION

Physical frailty, impaired cardiorespiratory fitness (CRF), and diminished lower limb function are prevalent in non-dialysis chronic kidney disease (NDD-CKD) and strongly associated with adverse clinical outcomes. This systematic review and meta-analysis aimed to evaluate the efficacy of exercise training interventions on the core dimensions of the frailty phenotype, CRF, and lower limb function in the NDD-CKD population.

METHODS

Seven electronic databases were systematically searched from inception to March 1, 2026, for randomized controlled trials (RCTs) comparing structured exercise interventions with usual care or sham exercise in adult NDD-CKD patients. Primary outcomes included the five core frailty phenotypes (absolute body weight, handgrip strength, walking speed, physical activity, and fatigue), CRF, and lower limb function. Data were synthesized using a random-effects model, reporting standardized mean differences (SMDs) with 95% confidence intervals (CIs). This study is registered with PROSPERO (CRD420261363651).

RESULTS

Eighteen RCTs encompassing 938 participants were included. Compared with the control group, exercise interventions significantly improved specific frailty dimensions, notably increasing walking speed (SMD = 0.36, 95% CI 0.03-0.69; P = 0.03) and alleviating fatigue (SMD = 0.34, 95% CI 0.04-0.64; P = 0.03). Furthermore, exercise significantly enhanced overall CRF (SMD = 0.46, 95% CI 0.29-0.63; P < 0.001) and lower limb function (SMD = 0.55, 95% CI 0.32-0.79; P < 0.001). Outcomes for absolute body weight, handgrip strength, and general physical activity levels did not reach statistical significance.

CONCLUSION

Exercise training is an effective and safe intervention method that can alleviate specific frailty characteristics (walking speed and fatigue), and enhance the cardiovascular and lower extremity functions of NDD-CKD patients. It is advocated to promote exercise as an early "pre-rehabilitation" strategy to enhance the physical functional reserve of patients before dialysis.

SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/prospero/, identifier CRD420261363651.