Global research trends and thematic evolution of respiratory microbiota in COPD: a bibliometric study

Chronic obstructive pulmonary disease (COPD) is increasingly recognized as a disorder influenced by the respiratory microbiota. Microbial dysbiosis has been linked to disease progression, inflammation, and clinical outcomes. However, a comprehensive overview of the global research landscape and evolving themes in this field is still lacking.

Publications on COPD and respiratory microbiota were retrieved from the Web of Science Core Collection (WoSCC) and Scopus databases. Bibliometric analyses, including publication trends, co-authorship networks, keyword co-occurrence, citation bursts, and thematic evolution, were conducted using VOSviewer, CiteSpace, and the bibliometrix package in R.

Between 2001 and 2025, 296 publications were identified in WoSCC and 433 in Scopus, reflecting a sustained growth in research output. Keyword co-occurrence and clustering analyses revealed three main research hotspots: (1) respiratory microbiota composition and dynamics, (2) pathogen colonization and inflammation-related processes, and (3) clinically relevant outcomes. Citation burst and thematic evolution analyses demonstrated a clear temporal shift from pathogen-centered studies toward microbiota-based, dynamic, and clinically oriented research paradigms. International collaboration is increasingly prominent, with China, the USA, and the UK leading in productivity and citation impact.

This bibliometric study systematically delineates the intellectual structure and evolving trends of COPD-related respiratory microbiota research. Our findings highlight the maturation of the field, reveal emerging research directions such as multi-omics integration and gut-lung axis interactions, and provide a quantitative reference for guiding future translational and microbiota-focused studies in COPD.