Effects of Exercise on Muscle Fitness in Dialysis Patients: A Systematic Review and Meta-Analysis

Abstract

Background: Lack of exercise is a prevalent problem in patients receiving dialysis. Although guidelines recommend these patients to undertake suitable exercise, no exercise type or intensity has been suggested, and the effect of exercise on muscle fitness in dialysis patients is not clear. This study investigated the effect of exercise on muscle fitness, including muscle mass, muscle strength, and physical performance, in patients on dialysis. Methods: A systematic review and a meta-analysis of randomized controlled trials (RCTs) were conducted. Five English and 4 Chinese databases were searched from their inception to July 2018. Two independent reviewers searched the different databases, selected trials, conducted bias assessment, and extracted the data. Results: A total of 21 RCTs meeting the inclusion criteria were included in this review. Pooled results demonstrated that resistance training significantly improved leg mass (standard mean difference [SMD] 0.34, 95% CI [0.06–0.62], p= 0.02) whereas aerobic training did not (SMD 0.87, 95% CI [–0.11 to 1.86], p = 0.08). Resistance training increased both grip strength (weighted mean difference [WMD] 4.71 kg, 95% CI [2.42–6.99], p < 0.00001) and knee extension strength (WMD 3.93 kg, 95% CI [0.59–7.28], p = 0.02) significantly. Aerobic training improved grip strength (WMD 7.70 kg, 95% CI [3.35–12.05], p= 0.005) and the time of finishing short version of the sit-to-stand test (STS; WMD –4.69 s, 95% CI [–9.01 to –0.38], p = 0.03) but with insufficient evidence. In the dimension of physical performance, both aerobic training and resistance training have some beneficial effect on improving the score of 6-min walking test (WMD 85.76 m, 95% CI [63.43–108.09], p < 0.00001; WMD 41.92 m, 95% CI [8.06–75.75], p = 0.02, respectively) and median version of STS test (WMD 4.30 repetitions, 95% CI [1.22–7.39], p = 0.006; WMD 2.60 repetitions, 95% CI [0.64–4.56], p = 0.006, respectively). Conclusions: Regular resistance training with a moderate to high intensity may lead to improvement in muscle mass and muscle strength of patients undergoing dialysis, especially for the trained muscles. Both aerobic training and resistance training may help dialysis patients improve physical performance.