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

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 (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 (MD = 79.26, 95% CI [72.69, 85.82], P < 0.00001) and other rehabilitation training group (MD = 23.64, 95% CI [6.70, 40.57], P = 0.006). The mMRC score (MD = −0.72, 95% CI [-1.09, -0.34], P = 0.002) and CAT (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.