Long-term pulse wave velocity outcomes with aerobic and resistance training in kidney transplant recipients - A pilot randomised controlled trial

PLoS One. 2017 Feb 3;12(2):e0171063 doi: 10.1371/journal.pone.0171063.
Abstract
BACKGROUND:

This pilot study examined long-term pulse wave velocity (PWV) and peak oxygen uptake (VO2peak) outcomes following a 12-week moderate-intensity aerobic or resistance training programme in kidney transplant recipients.

METHOD:

Single-blind, bi-centre randomised controlled parallel trial. 42 out of 60 participants completed a 9-month follow-up assessment (Aerobic training = 12, Resistance training = 10 and usual care = 20). Participants completed 12 weeks of twice-weekly supervised aerobic or resistance training. Following the 12-week exercise intervention, participants were transitioned to self-managed community exercise activity using motivational interviewing techniques. Usual care participants received usual encouragement for physical activity during routine clinical appointments in the transplant clinic. PWV, VO2peak, blood pressure and body weight were assessed at 12 weeks and 12 months, and compared to baseline.

RESULTS:

ANCOVA analysis, covarying for baseline values, age, and length of time on dialysis pre-transplantation, revealed a significant mean between-group difference in PWV of -1.30 m/sec (95%CI -2.44 to -0.17, p = 0.03) between resistance training and usual care groups. When comparing the aerobic training and usual care groups at 9-month follow-up, there was a mean difference of -1.05 m/sec (95%CI -2.11 to 0.017, p = 0.05). A significant mean between-group difference in relative VO2peak values of 2.2 ml/kg/min (95% CI 0.37 to 4.03, p = 0.02) when comparing aerobic training with usual care was revealed. There was no significant between group differences in body weight or blood pressure. There were no significant adverse effects associated with the interventions.

CONCLUSIONS:

Significant between-group differences in 9-month follow-up PWV existed when comparing resistance exercise intervention with usual care. A long-term between-group difference in VO2peak was only evident when comparing aerobic intervention with usual care. This pilot study, with a small sample size, did not aim to elucidate mechanistic mediators related to the exercise interventions. It is however suggested that a motivational interviewing approach, combined with appropriate transition to community training programmes, could maintain the improvements gained from the 12-week exercise interventions and further research in this area is therefore warranted.

TRIAL REGISTRATION:

study number: ISRCTN43892586.

CET Conclusion
Reviewer: Sir Peter Morris, Centre for Evidence in Transplantation, The Royal College of Surgeons of England.
Conclusion: In this pilot study the authors have examined in renal transplant recipients a 12 week moderate intensity aerobic or resistance training programme and compared the outcome with the usual care in a third group. They have examined pulse wave velocity (PWV) and peak oxygen uptake (VO2 peak) before and at the end of 12 weeks, and they have re-examined these parameters again at 12 months after entry. Forty-two of 60 participants completed the nine month follow-up assessment and so the numbers were small but there was an improved PWV, just significant, between resistance training and normal care groups. There was also a significant difference in VO2 peak values comparing aerobic training with usual care. There were no significance differences in body weight or blood pressure between the three groups and there were no significant adverse events associated with the interventions. The authors are fully aware of the weakness of the study, namely small numbers and a considerable number of drop-outs but they do suggest that a motivational interviewing approach combined with appropriate transition to community training programmes might be able to maintain the improvements gained from the 12 week exercise interventions, and that further research in this area is therefore warranted. This is a balanced conclusion in my mind. Obviously exercise is important for kidney transplant recipients but the problem is in providing the motivation to continue with exercise programmes either supervised or unsupervised.
Expert Review
Reviewer: Professor Ricardo González, Children´s Hospital "Auf der Bult", Hannover, Germany.
Conflicts of Interest: No
Clinical Impact Rating 3
Review: A well conducted study which can be considered preliminary and should be followed by similar studies with larger numbers of patients and longer follow up to confirm the validity of the findings.These findings are interesting in that they address the difficult problem of motivating renal transplant recipients to engage in regular physical exercise. Not surprisingly, both resistance training and anaerobic training for 12 weeks improve cardiovascular parameters that are associated with longevity. A motivational interviewing approach combined with appropriate transition to community training programs is suggested to extend the benefits of the original training beyond the supervised exercise period. These findings can probably be generalized to the entire renal transplant population and if confirmed should become standard practice.
Methodological quality
Jadad score 3
Allocation concealment YES
Data analysis MODIFIED INTENTION TO TREAT
Score based on Greenwood SA,et al. Aerobic or Resistance Training and Pulse Wave Velocity in Kidney Transplant Recipients: A 12-Week Pilot Randomized Controlled Trial (the Exercise in Renal Transplant [ExeRT] Trial) Am J Kidney Dis 2015 Oct
Study Details
Aims: To examine the long-term pulse wave velocity (PWV) and peak oxygen uptake (VO2peak) outcomes following a 12 week supervised aerobic or resistance training intervention in kidney transplant recipients.
Interventions: Participants were randomised after baseline assessment to either 12 weeks of supervised aerobic training (AT), resistance training (RT) or usual care. The AT or RT interventions included twice-weekly supervised, and once-weekly home-based, individually tailored exercise training as well as a once a week, 30-minute, physiotherapist led patient education.
Participants: Participants were those from the Exercise in Renal Transplant (ExeRT) study cohort* aged ≥18 years, who had received a kidney transplant in the preceding 12 months.
Outcomes: The primary outcome measured was PWV. Secondary outcomes measured included cardiorespiratory fitness, anthropometric measures and resting blood pressure.
Follow Up: 9 months
Metadata
Funding: Non-industry funding
Publication type: Randomized Controlled Trial, Randomised Controlled Trial
Trial registration: ISRCTN - 43892586
Organ: Kidney
Language: English
Author email: ellen.o'connor@nhs.net
MeSH terms: Adult; Exercise; Female; Humans; Kidney Transplantation; Male; Middle Aged; Pilot Projects; Pulse Wave Analysis; Resistance Training; Single-Blind Method