Respiratory Pathogens of Patients With Asthma and COPD Exacerbations

Inclusion Criteria: For COPD patients, patients who are admitted to the Prince of Wales Hospital with AECOPD will be screened for this study. AECOPD is defined when a patient with background COPD (with lung function parameters of FEV1/FVC ratio \<70%)24 presented with at least two of the following major symptoms (increased dyspnoea, increased sputum purulence, increased sputum volume) or one major and one minor symptom (nasal discharge/congestion, wheeze, sore throat, cough) for at least two consecutive days.25,26 Inclusion criteria: 1. Patients who has background COPD as mentioned above fulfilling the exacerbation criteria 2. Age ≥40 years For asthma patients, patients who are admitted to the Prince of Wales Hospital with asthma exacerbation will be screened for this study. Acute exacerbation of asthma is defined when an asthma patient presents with increasing dyspnea, wheeze or cough. Inclusion criteria: 1. Patients who has background asthma (defined as those with a consistent history and prior documented evidence of variable airflow obstruction, with evidence of an increase in FEV1 greater than 12% or 400 mL following bronchodilator or bronchial hyperresponsiveness on bronchial provocation testing, when stable)6 with any of the above exacerbation criteria for at least 2 consecutive days. 2. Age ≥18 years Control asthma and COPD subjects will be recruited from the respiratory clinic of the Prince of Wales Hospital. Subjects will be matched for age, sex and lung function of the COPD and asthma subjects. All recruited COPD subjects should have FEV1/FVC ratio of \<70%. For asthma patients, they should have a clinical diagnosis of asthma (defined as those with a consistent history and prior documented evidence of variable airflow obstruction, with evidence of an increase in FEV1 greater than 12% or 400 mL following bronchodilator or bronchial hyperresponsiveness on bronchial provocation testing, when stable). These subjects should have no exacerbation of asthma or COPD 6 weeks prior to the assessment. Exclusion Criteria: Exclusion criteria for all patients: 1. History of lung resection or other significant pulmonary disease like pulmonary fibrosis. 2. Active infection like pulmonary tuberculosis 3. Unable to complete assessment due to physical and/or cognitive impairment 4. Having short life expectancy like subjects with terminal malignancy or intractable heart failure.