The Characteristic of Airway Microbiome Profiling of COPD-bronchiectasis Overlap Patients and Its Association With Acute Exacerbation

Study Overview
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Brief Summary
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The overlap between chronic obstructive pulmonary disease (COPD) and bronchiectasis is a neglected area of research, and it is not covered by guidelines for clinical practice. COPD and bronchiectasis share common symptoms of cough with sputum production and susceptibility to recurrent exacerbations driven by new or persistent infection. Physiological criteria for the diagnosis of COPD and structural criteria for the diagnosis of bronchiectasis create the possibility for individual patients to fulfil both, resulting conceptually in either co-diagnosis or an overlap syndrome between the two conditions. The prevalence of this overlap will vary depending on the respective prevalence of COPD and bronchiectasis in the population under consideration. A recent study of 201 COPD patients with airway wall abnormalities typical of bronchiectasis confirmed an association with exacerbations and was predictive of mortality over 48 months. A further, single-centre study demonstrated a near three-fold increased mortality rate, with patients with bronchiectasis and associated COPD having a 5-year mortality of 55%, compared with 20% in those with bronchiectasis without COPD. Airflow obstruction is perhaps best considered one marker of disease severity in bronchiectasis. Disease-associated exacerbations have a major effect on patient healthcare costs as well as quality of life due to increased lung damage and mortality risk. Microorganisms such as Pseudomonas aeruginosa and, to a lesser extent, other Gram-negative and Gram-positive microorganisms identified in culture, have been linked to disease progression, poor clinical outcomes in bronchiectasis and driving airway neutrophil-mediated inflammation. The microbiome has the potential to provide valuable information regarding disease phenotype/endotype, treatment responses and targets for future therapy.

Official Title
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The Characteristic of Airway Microbiome Profiling of Chronic Obstructive Pulmonary Disease-bronchiectasis Overlap Patients and Its Association With Acute Exacerbation

Conditions
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Bronchiectasis Adult, Chronic Obstructive Pulmonary Disease, Overlap, Microbiome

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosed as COPD, bronchiectasis or overlap based on HRCT and lung function test. Aged between 18 and 80 years. Exclusion Criteria: Patients with active tuberculosis, traction bronchiectasis, malignancy, and severe systemic diseases.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The number of exacerbation events | The exacerbation of bronchiectasis is defined as a deterioration in three or more of the following key symptoms for at least 48 h: cough; sputum volume and/or consistency; sputum purulence; breathlessness and/or exercise tolerance; fatigue and/or malaise; haemoptysis AND a clinician determines that a change in bronchiectasis treatment is required. | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| α-diversity | α-diversity is a measure of how diverse a sample is based on how many species here are (richness) and how abundant each species is (evenness) within that sample. | 1 hour | 
| β-diversity | β-diversity is used to show how different samples are from each other, based on ifferences in bacterial presence, abundance or a phylogenetic tree | 1 hour | 
| The positive result of bacteria culture and viral PCR. | The positive result of bacteria is defined as at least one positive potentially-pathogenic bacteria being cultured from sputum (Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, Pseudomonas aeruginosa, or Staphylococcus aureus). The positive result of viral is defined as at least one positive viral PCR (HRV, RSV, influenza virus, parainfluenza virus, human metapneumovirus, adenovirus, human bocavirus, or coronavirus) from sputum. | 1 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Bronchiectasis, Chronic Obstructive Pulmonary Disease, overlap, microbiome, exacerbation