Study of Expiratory Airflow Limitation in COPD, Emphysema, and Asthma-COPD Overlap in Smokers with History of Heavy Smoking

What this Trial Is About

Researchers are investigating the site and mechanisms responsible for expiratory airflow limitation in people who have chronic obstructive pulmonary disease COPD, emphysema, or asthma-COPD overlap. The study focuses on current or former smokers with a history of more than 15 pack years who have mild to severe expiratory airflow limitation. It aims to understand whether airflow limitation is due to problems in large central airways, small peripheral airways, loss of lung elastic recoil, or a combination of these factors. Participants will undergo extensive lung function tests including spirometry before and after inhaled bronchodilation, lung volume measurements, diffusing capacity, and lung elasticity assessment involving an esophageal balloon. Imaging studies include high-resolution CT scans of the lungs to measure emphysema and bronchiectasis. Blood tests and possibly bronchoscopy may also be performed to gather additional information. The study groups are categorized based on clinical, pathologic, laboratory, physiological, and radiological differences. During the study, participants will have assessments including lung function tests, blood tests, exhaled nitric oxide measurement, and imaging scans. Some tests may be uncomfortable but are expected to cause no harm. The primary measurement is to identify the site and mechanisms of expiratory airflow limitation over a four-year period. The study started in 2017 and is planned to continue through 2027, with participant involvement varying depending on the tests performed.

Site and Mechanism(s) of Expiratory Airflow Limitation in COPD, Emphysema and Asthma-COPD Overlap