Global Research Landscape and Clinical Hotspots in COPD-OSA Overlap Syndrome: A Bibliometric and Visualization Analysis.

BACKGROUND: This study systematically depicts the global research landscape, knowledge base, and thematic evolution of chronic obstructive pulmonary disease combined with obstructive sleep apnea overlap syndrome (COPD-OSA overlap syndrome), providing a reference for subsequent research and clinical translation. METHODS: Relevant literature published between 2000 and 2025 was retrieved from the Web of Science Core Collection, Scopus, and PubMed databases. Records from Web of Science and Scopus were merged and deduplicated to construct the primary bibliometric dataset, while PubMed was analyzed separately as a supplementary source for cross-database comparison using keywords and MeSH terms. Bibliometrix, VOSviewer, and CiteSpace were used to analyze research output, collaboration networks, core sources, co-citation structure, and research hotspots. A latent Dirichlet allocation (LDA) model was applied to identify latent topics and their temporal trends. RESULTS: The primary dataset included 1239 publications, with an average annual growth rate of 20.62%; publication volume increased markedly after 2017. The United States, China, and Italy ranked highest in publication count, yet the overall international co-authorship rate was only 6.3%. The field's knowledge base centers on nocturnal hypoxemia, cardiovascular outcomes, acute exacerbations, and positive airway pressure therapy. The LDA model identified 10 latent topics, with two showing significant upward trends (COVID-19 with OSA; acute cardiovascular events and adipose tissue) and one showing a downward trend (anthropometry and lung function parameters). The 274 PubMed-included articles complemented cross-database comparisons and indicated growing attention to cognitive function, oxygen saturation, and digital screening. CONCLUSION: Research on COPD-OSA overlap syndrome is shifting from describing disease coexistence toward complex multimorbidity, risk stratification, and individualized management. However, international collaboration and high-level clinical evidence remain insufficient. Future work should standardize case definitions, establish multicenter longitudinal cohorts, and conduct phenotype-based treatment studies.