The gut microbiota in chronic obstructive pulmonary disease varies by CT-verified emphysema status

Single-centre case-control study with 62 current and former smoking COPD patients and 49 controls. DNA was extracted from stool samples, and the V3V4-region of the bacterial 16S-rRNA gene was sequenced. Emphysema was defined based on thoracic computed tomography (CT thorax) low attenuating areas ≥/<10% at threshold -950 and -910 Hounsfield units respectively.

Microbial data were analysed with QIIME 2 and R. Results The genus Veillonella was decreased and a genus belonging to class Clostridia was increased in COPD compared to healthy controls. Beta diversity measure Bray Curtis differed in emphysema compared to controls, and 27 genera were differentially abundant in emphysema vs. controls. Nine of these genera belonged to the family Lachnospiraceae.

Lung function, blood counts and COPD assessment test scores were correlated with the relative abundance of several genera. Some of the genera showing the strongest correlation to lung function belonged to the family Lachnospiraceae. Conclusion We found small but statistically significant differences in the gut microbiota of COPD versus controls.

Larger differences were seen in the gut microbiota according to CT-verified emphysema status. Correlations between the gut microbiota and lung function, blood cell counts, and CAT score were found.