The national COPD screening program is in a cross-sectional manner at the baseline, planning to recruit a total of 800,000 participants from 160 districts or counties (5,000 for each site on average) from 31 provinces, autonomous regions or municipalities directly under the central government of China. The filtered COPD high-risk population and confirmed COPD patients will be managed and followed up according to the standardized clinical guidelines. The major aims of the program are to estimate the prevalences of COPD high-risk population and under- or miss- diagnosed COPD patients, and to manage the development and outcomes of the disease.

Inclusion Criteria:

• adults aged between 35 and 75 years;
• residents living in the survey area with more than 6 months in the past year.

Exclusion Criteria:

• experienced myocardial infarction, stroke or shock in the past 3 months;
• experienced severe cardiac insufficiency, severe arrhythmia or unstable angina pectoris in the past 4 weeks;
• experienced massive hemoptysis in the past 4 weeks;
• received chest, abdominal or ophthalmic surgery in the past 3 months;
• have mental disorders (e.g. auditory hallucinations, visual hallucinations, taking antipsychotics, seizures requiring medication, etc.);
• have cognitive impairment (e.g. dementia, comprehension impairment, etc.);
• have uncontrolled hypertension (i.e. systolic blood pressure > 200 mmHg, diastolic blood pressure > 100 mmHg);
• present with heart rate >120 beats/min;
• have aortic aneurysm;
• have severe hyperthyroidism;
• are pregnant or lactating women;
• experienced respiratory infectious diseases (e.g. tuberculosis, influenza, etc.) in the past month.

Adults who are potentially under a high risk of suffering COPD with an age between 35 and 75 years are eligible to be recruited. The participants should be residents who were living in the survey area with more than six months in the past year.

Data would be available on reasonable request from the principal investigator.