Breathing Exercises in the Treatment of COPD: An Overview of Systematic Reviews

Background: The effectiveness of breathing exercises in the treatment of chronic obstructive pulmonary disease (COPD) has been demonstrated in several systematic reviews (SRs), but a comprehensive review is still lacking. The aim of this study was to synthesize evidence from SRs, to summarise the effects of breathing exercises interventions for COPD patients. Methods: We conducted an overview of the SRs of breathing exercises in the treatment of COPD. We include Systematic Reviews of randomized-controlled clinical trials. In the included COPD, control of breathing exercises alone was the only variable and no restriction was placed on relevant outcome measures. The SRs were screened by computer retrieval from the Chinese National Knowledge Infrastructure (CNKI), WanFang database, Chinese Science and Technology Journal Database (CSTJ), Chinese Biological Medicine (CBM), MEDLINE (PubMed), Embase, Cochrane library, and Web of Science. The Risk of Bias in Systematic reviews (ROBIS) tool, the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement, a Measure Tool to Assess Systematic Reviews (AMSTAR) 2, and the Grades of Recommendations, Assessment, Development and Evaluation (GRADE) were used to evaluate the risk of bias, reporting quality, methodology quality, and evidence quality. Results: Nine SRs met the inclusion criteria and were included in the overview, 4 SRs in Chinese, and 3 SRs in English. All the SRs were published between 2015-2021. According to the ROBIS tool, 4 SRs (57.14%) were rated as low risk of bias. The PRISMA scale showed that 5 SRs had some defects, and 2 SRs were relatively complete. Reporting deficiencies exist primarily in protocol and registration (28.6%), search (42.9%), risk of bias across studies (0%), additional analyses (42.9%), and funding (28.6%). Based on the AMSTAR-2 scale, 3 SRs were low quality, and the other 4 SRs were very low. The result of evidence quality assessment showed that among the 34 outcomes involved in the 7 studies, 19 were low-level outcomes, 15 were very low-level outcomes, and there were no moderate and high-level quality outcomes. Limitations and publication bias were two major factors that reduced the quality of evidence. Conclusion: Breathing exercises in certain can improve pulmonary function, exercise endurance, dyspnea, quality of life, and respiratory muscle strength of COPD patients. However, there is an urgent need for high-quality studies to guide clinical practice due to certain deficiencies in reporting quality and the low quality of methodology and outcomes.