Resistance (exercise) training in non-dialysis dependent chronic kidney disease (ckd stage 3) and validation of ultrasound in the measurement of muscle size and structure in haemodialysis patients (ckd stage 5)

Abstract

AIM: This thesis set out to make an original contribution to knowledge with regard to methods of assessing muscle size and architecture in the CKD and ESRD population, and to assess the ability to improve the muscle size and architecture, and symptoms of uraemia, by implementing an anabolic intervention (resistance exercise training) in the CKD population. OUTCOME MEASURES: Ultrasound was shown to have high validity (against gold standard MRI measures; ICCs: VLACSA 0.96, VL depth 0.99, fat depth 0.98) and intra-rater reliability (ICCs: VL depth 0.98, total muscle depth 0.97, fat depth 0.99; MDC: VL depth 0.14cm, total muscle depth 0.19cm, fat depth 0.22cm) in measuring regional body composition at the mid-VL site in the CKD population. There were significant (p<0.01) correlations between US-derived measures of (mid-VL) muscle size and architecture with strength and function (larger muscle mass and/or pennation angle positively correlated with higher strength and/or functional performance). Patient-reported uraemic symptoms were worse (p<0.01) in those with reduced strength and/or function. INTERVENTION RESULTS: An anabolic (resistance training) intervention (12-weeks, randomized to once [RT1 n=7] or three times [RT3 n=10] per week, 80%1RM) brought about significant improvements over time (p<0.01) in all measures of muscle size and architecture (VL depth, total muscle depth, VLACSA, pennation angle). Interaction effects (group*time) were only seen in pennation angle (p<0.05) and VLACSA (p<0.01) where RT3 gains were greater than RT1 from week 8 onwards. All measures of strength, function, and uraemic symptoms improved over time (p<0.01) with no interaction effects (no difference from greater training frequency/ volume). CLINICAL AND RESEARCH IMPLICATIONS: The intervention results suggest implementing a RT form of “prehabilitation” in early stage (CKD3) patients just once per week is sufficient to bring about statistically and clinically important changes in strength and function that benefit the patient through reduced frequency and/or intrusiveness of uraemic symptoms (improved health-related quality of life), with minimal time-commitment. Further research should examine if there is additional benefit to the significantly greater increases in VLACSA and pennation angle observed in RT3, with regards to long-term maintenance of functional improvements, and whether an RT1 or RT3 programme delays the progression of CKD, the need for RRT, and patient mortality.