Fig. 4

Sputum microbiome networks in COPD patients in different phenotypic subgroups. The networks of the top 15 genera were built using Spearman correlation coefficients in COPD patients. In total, 12 and 9 nodes were constructed in the LRE (a) and HRE groups (b), respectively. The nodes represent bacterial genera. The red and blue lines represent positive and negative correlations, respectively. Heatmap of the Spearman correlation matrix from the LRE (c) or HRE groups (d) with the top 15 genera. In the figure, the larger the circle, the higher is the correlation coefficient. Red dots represent positive correlations, and blue dots represent negative correlations. The correlation values ranged from − 1.00 (blue) to 1.00 (red). LRE low-risk exacerbator, HRE high-risk exacerbator