AbstractChronic obstructive pulmonary disease (COPD) is a respiratory disease with a high incidence, mortality, and disability rate. Because there are few symptoms in the early stages of COPD, diagnosis and treatment are seriously insufficient. It is necessary to find effective clues for early COPD diagnosis and provide appropriate interventions. Several studies suggest that small airway disease is the earliest stage of COPD because it is correlated with subsequent development of airflow obstruction. However, there are currently no globally accepted criteria for defining early COPD. This study mainly introduced risk factors, definition, diagnosis, and treatment of early COPD from a new perspective.
