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

Background and aim The association of the gut microbiota to chronic
obstructive pulmonary disease (COPD) phenotypes is underexplored. We aimed
to compare stool samples from COPD patients and healthy controls and
relate findings to common COPD phenotypes. Methods 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.