AUTHOR=Pan Juan , Zhang Yanjie , Qiu Songlin , Peng Shuotao , Kang Haixin , Tung Tao-Hsin , Shen Bo TITLE=Gut microbiome dysbiosis in chronic lung disease: a systematic review and meta-analysis JOURNAL=Frontiers in Cellular and Infection Microbiology VOLUME=Volume 15 - 2025 YEAR=2025 URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2025.1554846 DOI=10.3389/fcimb.2025.1554846 ISSN=2235-2988 ABSTRACT=ObjectivesRecent data suggest that the gut–lung axis plays a role in the development of lung disease. However, the potential association between the gut microbiota and chronic lung disease (CLD) remains unclear. This study aimed to investigate changes in the gut microbiome in patients with CLD.MethodsWe searched PubMed, Web of Science, Cochrane, Embase, China National Knowledge Infrastructure, Wanfang, and VIPC databases from inception to August 1, 2024. The inclusion criteria involved studies that reported on gut flora in patients with CLD. Two independent reviewers used standardized methods to search, screen, and code included studies. Publication bias was analyzed using Egger’s test. Changes in the gut microbiome were assessed through α-diversity, β-diversity, and changes/differences in relative abundance, and results were evaluated using a random-effects model.ResultsA total of 27 studies were included: 21 on chronic obstructive pulmonary disease (COPD; 1,273 patients and 6,718 healthy controls [HCs]), six on asthma (559 patients and 5,310 HCs), one on COPD and asthma combined, and one on pulmonary cystic fibrosis. Compared with HCs, α-diversity was decreased in patients with COPD (Shannon index: standard mean difference [SMD] = −0.38; 95% confidence interval [CI], −0.76 to 0.00, I2 = 72%; n=7). In COPD, Bacteroides was increased (SMD = 0.76; 95% CI, 0.00 to 1.52; I2 = 91%; n=4), while Bifidobacterium (SMD = −0.88; 95% CI, −1.39 to −0.37; I2 = 88%; n=5) and Lactobacillus (SMD = -0.73; 95% CI, -1.00 to -0.46; I2 = 66%; n=5) were decreased. No difference was found in Shannon and Simpson diversity indexes between patients with asthma and HCs.ConclusionThe gut microbiota of patients with COPD is imbalanced, and the abundance of probiotics is lower than in healthy individuals. Further exploration of the potential role of probiotics in COPD may provide promising targets for treatment.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022378296.