Cardiorespiratory fitness in kidney transplant recipients: A pilot randomised controlled trial of structured home-based rehabilitation and a nested case-control analysis

Objectives(1) Explore the effects of a 12-week home-based rehabilitation programme on cardiorespiratory fitness in kidney transplant recipients; (2) Compare cardiorespiratory fitness parameters in kidney transplant recipients and age-sex matched healthy volunteers to aid the justification for routine rehabilitation programmes.DesignPilot randomised controlled trial with nested case-control.SettingHome-based rehabilitation; hospital-based outcome assessments.ParticipantsPilot randomised controlled trial: 50 stable kidney transplant recipients (>1 year post-transplant) (randomised 1:1; <i>n</i> = 25 control and <i>n</i> = 25 intervention). Nested case-control: 30 kidney transplant recipients and 30 healthy volunteers.InterventionA 12-week home-based aerobic and resistance rehabilitation programme or guideline-directed care control.Main measuresCardiorespiratory fitness measured by cardiopulmonary exercise testing.ResultsPilot randomised controlled trial: After adjusting for baseline, follow-up values were significantly greater in intervention compared to control for peak oxygen uptake (V̇O_2peak) mL/kg/min, (+1.50, <i>p</i> = .03) and maximum workload (+8 W, <i>p</i> = .04) but not V̇O_2peak L/min or variables at the gas exchange threshold. Higher frequency of aerobic exercise sessions was associated with greater improvements in cardiorespiratory fitness (<i>R</i>₂ = .252, <i>p</i> = .040).Nested case-control: V̇O_2peak was reduced in kidney transplant recipients compared to healthy volunteers (18.81 ± 4.61 vs 24.06 ± 5.72 mL/kg/min; <i>p</i> < .01), as was V̇O₂ at the gas exchange threshold (11.70 ± 2.67 vs 14.47 ± 3.39 mL/kg/min; <i>p</i> < .01).ConclusionsA 12-week home-based rehabilitation programme induced a significant improvement in some cardiorespiratory fitness variables and higher frequency of aerobic exercise associated with greater improvements. Cardiorespiratory fitness is significantly impaired in kidney transplant recipients compared to age-sex-matched healthy volunteers. Together, these findings highlight the clinical importance of promoting aerobic exercise and the integration of rehabilitation programmes into routine care for this population.Trial registrationClinicalTrials.gov, NCT04123951 (https://clinicaltrials.gov/study/NCT04123951).