Randomized controlled trial of intradialytic resistance training to target muscle wasting in ESRD: the Progressive Exercise for Anabolism in Kidney Disease (PEAK) study.
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.


METHODS
Randomized controlled trial.


METHODS
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).


METHODS
Two sets of 10 free-weight PRT exercises were performed at a high intensity during routine thrice-weekly hemodialysis treatment under direct supervision.


METHODS
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 cm(2)) compared with losses in the 12WK group (-1.37 +/- 6.87 cm(2); 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.


CONCLUSIONS
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.
Cheema
Bobby
B
School of Exercise and Sport Science, University of Sydney, Sydney, Australia. b.cheema@massey.ac.nz
Abas
Haifa
H
Smith
Benjamin
B
O'Sullivan
Anthony
A
Chan
Maria
M
Patwardhan
Aditi
A
Kelly
John
J
Gillin
Adrian
A
Pang
Glen
G
Lloyd
Brad
B
Fiatarone Singh
Maria
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D018908:Muscle Weakness / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D006435:Renal Dialysis / Q000379:methods*