Background The respiratory microbiome is altered in COPD patients but its relationship with core components of the disease, such as the severity of airflow limitation, the frequency of exacerbations or the circulating levels of eosinophils, is unclear. Methods Cross-sectional study comprising 72 clinically stable COPD patients (mean age 68 [SD 7.9] years; FEV1 48.7 [SD 20.1]% of reference) who provided spontaneous sputum samples for 16S rRNA gene amplification and sequencing. The microbiome composition was analysed with QIIME. Results We observed that: (1) more severe airflow limitation was associated with reduced relative abundance (RA) of Treponema and an increase in Pseudomonas ; (2) patients with ≥2 exacerbations the previous year showed a significantly different bacterial community with respect to non-exacerbators ( p = 0.014), with changes in 13 genera, including an increase of Pseudomonas, and finally, (3) peripheral eosinophils levels ≥2% were associated with more diverse microbiome [Chao1 224.51 (74.88) vs 277.39 (78.92) p = 0.006; Shannon 3.94 (1.05) vs 4.54 (1.06) p = 0.020], and a significant increase in the RAs of 20 genera. Conclusion The respiratory microbiome in clinically stable COPD patients varies significantly according to the severity of airflow limitation, previous history of exacerbations and circulating eosinophils levels. Electronic supplementary material The online version of this article (10.1186/s12890-019-0867-x) contains supplementary material, which is available to authorized users.

BackgroundPulmonary rehabilitation (PR) is recommended after a severe COPD exacerbation, but its short- and long-term effects on health care utilization have not been fully established.AimsThe aims of this study were to evaluate patient compliance with a chronic disease management (CDM) program incorporating home-based exercise training as the main component after a severe COPD exacerbation and to determine its effects on health care utilization in the following year.Materials and methodsCOPD patients with a severe exacerbation were included in a case-cohort study at admission. An intervention group participated in a nurse-supervised CDM program during the 2 months after discharge, comprising of home-based PR with exercise components directly supervised by a physiotherapist, while the remaining patients followed usual care.ResultsNineteen of the twenty-one participants (90.5%) were compliant with the CDM program and were compared with 29 usual-care patients. Compliance with the program was associated with statistically significant reductions in admissions due to respiratory disease in the following year (median [interquartile range]: 0 [0–1] vs 1 [0–2.5]; P=0.022) and in days of admission (0 [0–7] vs 7 [0–12]; P=0.034), and multiple linear regression analysis confirmed the protective effect of the CDM program (β coefficient −0.785, P=0.014, and R2=0.219).ConclusionA CDM program incorporating exercise training for COPD patients without limiting comorbidities after a severe exacerbation achieves high compliance and reduces admissions in the year following after the intervention.

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