Fig. 2From: Relationship between gut microbiota and lung function decline in patients with chronic obstructive pulmonary disease: a 1-year follow-up studyThe indices for community richness (A Chao 1 index) and diversity (B and C Shannon and Simpson indices) of four COPD groups. *p < 0.05, Wilcoxon test. C: control; D: decline; S1: stage 1; S2: stage 2Back to article page