Characteristics of Gut Microbiota in Patients with Chronic Obstructive Pulmonary Disease Based on Metagenomics and Metabolomics

The gut–lung axis is important in Chronic Obstructive Pulmonary Disease (COPD) pathogenesis; however, most studies rely on low-resolution 16S rRNA sequencing, and integrated multi-omics investigations in Chinese COPD populations are scarce. A total of 104 participants including 74 stable COPD patients and 30 healthy controls from northern China were recruited, and shotgun metagenomic sequencing and untargeted metabolomics were performed. Results showed that alpha diversity of the gut microbiota did not differ significantly between COPD patients and healthy controls, whereas beta diversity showed clear separation. Marked differences in microbial composition from phylum to species levels (e.g., Oscillospiraceae) and altered microbial functions (signal transduction, antibiotic resistance, etc.) were observed in COPD patients. Metabolomic profiling identified 497 differential fecal metabolites and 1260 differential serum metabolites in COPD patients. Importantly, serum riboflavin levels were significantly reduced and positively correlated with pulmonary function indices as well as the key differential gut microbial functional gene K11752. Serum metabolite eremopetasinorol exhibited high diagnostic accuracy for COPD (AUC = 0.947, 95% CI: 0.8–0.98), surpassing fecal metabolites and microbial features. This study provides integrated metagenomic and metabolomic characterization of gut microbiota alterations in Chinese COPD patients, offering novel insights for biomarker discovery and targeted intervention strategies.