Effect of Endurance Training in COPD Patients Undergoing Pulmonary Rehabilitation: A Meta-Analysis

Abstract

Background. The efficacy of endurance training (ET) on patients with chronic obstructive pulmonary disease (COPD) has been controversial. This study was aimed at meta-analyzing the effect of ET in COPD patients undergoing pulmonary rehabilitation. Methods. The literature retrieval was performed in databases to screen relevant literature. Inclusion criteria were as follows: (1) subjects—COPD patients; (2) inclusion of interventional and control groups; (3) intervention measures—the interventional group received whole-body ET and other lung rehabilitation training, while the control group did not receive intervention or other lung rehabilitation training; (4) outcome indicators which included at least one of the following—6MWD, modified Medical Research Council questionnaire (mMRC), and COPD Assessment Test (CAT); and (5) study type—randomized controlled trials (RCTs). The Cochrane risk-of-bias tool was used to assess the risk of bias. The chi-square test was used to evaluate the magnitude of heterogeneity. Subgroup analysis was used to explore the source of heterogeneity. A funnel plot and Egger’s test were used to evaluate publication bias. Results. The 6MWD in the ET group was significantly higher than that in the control group ( $\text{MD}=47.20$ , 95% CI [28.60, 65.79], $P<0.00001$ ). Significant heterogeneity ( $P<0.00001$ , $I^2=76\%$ ) without publication bias ( $P>0.05$ ) was noted. Subgroup analysis showed that the 6MWD of the ET group was significantly larger than that of the control group without heterogeneity ( $P=0.63$ , $I^2=0\%$ ; $P=0.59$ , $I^2=0\%$ ) in both the no training subgroup ( $\text{MD}=79.26$ , 95% CI [72.69, 85.82], $P<0.00001$ ) and other rehabilitation training group ( $\text{MD}=23.64$ , 95% CI [6.70, 40.57], $P=0.006$ ). The mMRC score ( $\text{MD}=-0.72$ , 95% CI [-1.09, -0.34], $P=0.002$ ) and CAT ( $\text{MD}=-6.07$ , 95% CI [-7.28, -4.87], $P<0.00001$ ) of the ET group were significantly lower than those of the control group. There was no heterogeneity ( $P=0.32$ , $I^2=15\%$ ; $P=0.16$ , $I^2=41\%$ ). Conclusion. ET can improve patients’ motor function and reduce dyspnea. ET might be incorporated as an important part of lung rehabilitation training.