Sputum Microbiome Is Associated with 1-Year Mortality after Chronic Obstructive Pulmonary Disease Hospitalizations.

Lung dysbiosis promotes airway inflammation and decreased local immunity, potentially playing a role in the pathogenesis of acute exacerbations of chronic obstructive pulmonary disease (AECOPD). We sought to determine the relationship between sputum microbiome at the time of AECOPD hospitalization and 1-year mortality in a COPD cohort. We used sputum samples from 102 patients hospitalized because of AECOPD. All subjects were followed for 1 year after discharge. The microbiome profile was assessed through sequencing of 16S rRNA gene. Microbiome analyses were performed according to 1-year mortality status. To investigate the effect of α-diversity measures and taxon features on time to death, we applied Cox proportional hazards regression models and obtained hazard ratios (HRs) associated with these variables. We observed significantly lower values of α-diversity (richness, Shannon index, evenness, and Faith's Phylogenetic Diversity) among nonsurvivors ( = 19, 18.6%) than survivors ( = 83, 81.4%). β-Diversity analysis also demonstrated significant differences between both groups (adjusted permutational multivariate ANOVA,  = 0.010). The survivors had a higher relative abundance of ; in contrast, nonsurvivors had a higher abundance of . The adjusted HRs for 1-year mortality increased significantly with decreasing α-diversity. We also observed lower survival among patients in whom sputum samples were negative for (HR, 13.5; 95% confidence interval, 4.2-43.9;  < 0.001) or positive for (HR, 7.3; 95% confidence interval, 1.6-33.2;  = 0.01). The microbiome profile of sputum in AECOPD is associated with 1-year mortality and may be used to identify subjects with a poor prognosis at the time of hospitalization.