Clinical Characteristics of Asthma and COPD Overlap for Patients With Asthma and COPD in Hong Kong

Rationale:

Around 15 to 20% of COPD patients have features of asthma. These patients have more frequent and more severe exacerbations, and higher medical utilization. The Global Initiative for Asthma (GINA) and Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines have given joint recommendations on the identification, diagnosis and treatment of these patients having Asthma-COPD Overlap (ACO). These are at present expert opinions and further studies are needed to establish the optimal definitions and treatment options. The recommendations proposed by the guidelines have been adapted for use in the Asia area countries. Nonetheless, the application to clinical practice has not been well established and there are no prevalence data available on the COPD with asthma symptom population or asthma with COPD symptoms population based on the recommended features for identification. This is the current data gap in Asia.

Primary objective:

To determine the proportion and clinical characteristics of patients with ACO as defined by the joint GINA and GOLD recommendation amongst diagnosed COPD and asthma patients seen at the out-patient clinics

Inclusion criteria

Subjects must fulfil all of the following criteria:

• All patients with confirmed diagnosis of COPD (post-bronchodilator FEV1/FVC<0.7 based on the medical records) 1 or 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
• Aged >40 years old
• Signed written informed consent to participate in the study

Exclusion criteria

• Patients currently with acute exacerbation of COPD by GOLD definition (any worsening of a patient's respiratory symptoms that is beyond normal day-to-day variations and requires a change in medication) 1 or acute exacerbation of asthma by GINA guideline. 6
• Patients with respiratory diseases that can show similar symptoms to chronic airway diseases such as bronchiectasis, tuberculosis (TB)-destroyed lung parenchyma, endobronchial TB, and lung cancer, or those who have history of these diseases based on physician's judgment
• Patients currently diagnosed with pneumonia and acute bronchitis
• Patients currently randomized in other clinical studies