Exercise As Adjunctive Therapy In Chronic Kidney Disease
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Abstract
Background. Exercise is a natural medicine that has been prescribed for the
prevention and management of chronic diseases, to enhance quality of life, improve
health status and promote longevity. Current efforts to implement exercise as routine
practice in the conventional renal replacement therapy population have been hampered
by a lack of randomised controlled data. The aim of this thesis was to investigate the
effect of exercise as an adjunctive therapy to enhance outcomes pertaining to renal
transplantation, vascular access, haemodialysis adequacy and muscle wasting in Stages
four and five Chronic Kidney Disease patients. It was hypothesised that randomised
controlled trials employing gold standard outcome measures would reveal significant
beneficial effects of exercise that are strongly associated with quality of life,
hospitalisation and survival in this patient population.
Reports. The first report presents a systematic literature review of exercise in the
kidney transplant population. The largest positive effects were noted on intermediate
outcomes such as aerobic fitness and muscle strength. Presumably these adaptations
contributed to the trends observed for improvement in quality of life. Whether exercise
impacts on outcomes associated with longevity of life requires further study.
The rest of the thesis focused on patients receiving the more popular form of renal
replacement therapy, haemodialysis. The first empirical study of the thesis appertaining
to vascular access investigated the feasibility of implementing a post-operative forearm
exercise intervention for arteriovenous fistula maturation. Exercise had no effect on
primary outcomes measures of arterial diameter (95% CI, -0.24 [-1.12; 0.51] mm) and
venous diameter (95% CI, 0.16 [-1.84; 1.24] mm). It was concluded that future
randomized controlled trials should investigate a similar protocol implemented before
arteriovenous fistula creation to enhance surgery success and maturation.
The second randomised controlled trial explored the effect of intradialytic
exercise in comparison to the traditional prescription of increased dialysis time to
enhance dialysis adequacy and solute removal. Increased haemodialysis time, but not
exercise, increased equilibrated Kt/Vurea compared to control trials (Extra time vs.
control: 95% CI, 0.15 [0.05; 0.26]; exercise vs. control: 95% CI, 0.03 [-0.05; 0.12]).
Exercise, but not increased time, increased phosphate reduction ratio (exercise vs.
control: 95% CI, 8.6 [0.5; 16.7] %; extra time vs. control: 95% CI, 5.0 [-1.0; 11.1] %).
Thus intradialytic exercise cannot replace the traditional prescription of increased
haemodialysis time, but may be a useful adjunctive therapy for serum phosphate
control.
The third study implemented a randomised controlled trial of intradialytic
progressive resistance training for muscle wasting. The primary outcome measure of
thigh muscle volume, as measured by magnetic resonance imaging, significantly
increased following 12 weeks of training compared to a sham exercise control (95% CI,
193 [63; 324] cm3
). Intradialytic resistance exercise elicited an anabolic and strength
response in haemodialysis patients. However, a surprising lack of a change in functional
capacity despite increased muscle mass warrants further investigation.
Conclusion. The findings suggested that exercise had a beneficial effect on
factors relating to outcomes in Stages 4 and 5 Chronic Kidney Disease patients.
However, to ensure effectiveness of interventions and to maximize programme
efficiency, careful consideration of basic exercise and physiological principles is
required. Nevertheless, the observed benefits of exercising outweighed its risks thus
supporting the initiative for exercise prescription as an adjunctive therapy for the
management of this disease state