Randomized Controlled Trial of Intradialytic Resistance Training to Target Muscle Wasting in ESRD: The Progressive Exercise for Anabolism in Kidney Disease (PEAK) Study
Received 28 November 2006; accepted 10 July 2007.
Background
To determine whether prolonged (24 weeks) intradialytic progressive resistance training (PRT) could counteract muscle wasting more effectively than short-duration training (12 weeks) in patients with end-stage renal disease.
Study Design
Randomized controlled trial.
Setting & Participants
49 patients (age, 62.6 ± 14.2 years; 0.3 to 16.7 years on hemodialysis therapy) were randomly assigned to PRT plus usual care for 24 weeks (24WK group) or a crossover control group that received usual care for the first 12 weeks, then PRT plus usual care for the latter 12 weeks (12WK group).
Intervention
Two sets of 10 free-weight PRT exercises were performed at a high intensity during routine thrice-weekly hemodialysis treatment under direct supervision.
Outcomes & Measurements
Primary outcomes include thigh muscle cross-sectional area by means of computed tomography and intramuscular lipid content estimated through attenuation. Secondary outcomes include muscular strength, exercise capacity, and C-reactive protein level.
Results
The 24WK group increased muscle cross-sectional area (+1.82 ± 3.25 cm2) compared with losses in the 12WK group (−1.37 ± 6.87 cm2; relative effect size, 0.59; 95% confidence interval [CI], −0.27 to 6.65; P = 0.04). However, this outcome did not achieve the level of statistical significance required (P = 0.025) after Bonferroni correction for multiple primary outcomes. There was no significant change in intramuscular lipid content between groups (+0.19 ± 1.32 versus +0.16 ± 1.69 Hounsfield units in the 24WK and 12WK groups, respectively; P = 0.31). Log C-reactive protein level tended to decrease in the 24WK group compared with the 12WK group (relative effect size, −0.63; 95% CI, −0.27 [−0.54 to 0.00]; P = 0.05). The 24WK group improved muscular strength measures and exercise capacity throughout the trial.
Limitations
Single geographic site used; no control group without exercise exposure; unblinded assessment of some secondary outcome measures.
Conclusions
Prolonged intradialytic PRT did not significantly improve muscle cross-sectional area or intramuscular lipid content compared with a shorter duration of exercise. Future trials are required to more thoroughly investigate the clinical importance and magnitude of myogenic adaptations to PRT in this cohort.
1School of Exercise and Sport Science, University of Sydney, Sydney, Australia
2Institute of Food, Nutrition, and Human Health, Massey University, Wellington, New Zealand
3Department of Medicine, University of New South Wales, Sydney, Australia
4Department of Nutrition and Dietetics, St George Hospital, Sydney, Australia
5Department of Nutrition and Dietetics, Royal Prince Alfred Hospital, Sydney, Australia
6Department of Renal Medicine, St George Hospital, Sydney, Australia
7Department of Renal Medicine, Royal Prince Alfred Hospital, Sydney, Australia
8Faculty of Medicine, University of Sydney, Sydney, Australia
9Hebrew SeniorLife and Jean Mayer USDA Human Nutrition Center on Aging, Tufts University, Boston, MA.
Address correspondence to Bobby Cheema, PhD, Institute of Food, Nutrition and Human Health, Te Kura Hangarua o Kai-oranga-a-tangata, Massey University, Wellington Campus, Private Bag 756, Wellington, New Zealand.
Trial registration: www.actr.org.au; study number: 12605000101684.
ABSTRACT