Central Airway Collapse Triggers Worse Events, Study Finds

A study has found that expiratory central airway collapse (ECAC) leads to a worse respiratory quality of life. The study was published in the Journal of the American Medical Association on February 2, 2016, and was conducted by Surya P. Bhatt, MD, of the Division of Pulmonary, Allergy and Critical Care Medicine at the University of Alabama Birmingham, and colleagues.

The researchers began with the aim of discovering whether or not ECAC leads to respiratory morbidity in smokers, regardless of any underlying lung disease. They used computed tomography (CT) scans to determine if ECAC existed, and St. George’s Questionnaire (SGRQ) to determine the baseline respiratory quality of life for 8820 participants, some of whom had chronic obstructive lung diseases, and some who were not diagnosed with the condition.

Current and former smokers were included in the study, and participants were aged between 45 and 80 years old. All participants had been part of the COPDGene study previously. There were 4667 men (56.7%), 5428 (66%) white people, 2792 African Americans (34%), and 4559 (51.7%) were current smokers. Additionally 3856 (43.7%) had been diagnosed with COPD. The researchers identified 443 cases of ECAC and found that there were more cases of ECAC among the participants who had been diagnosed with COPD.

This cohort of study participants was considered high risk because it consisted of current and former smokers, and according to the researchers “the prevalence of ECAC was 5%, and presence of ECAC was associated with worse respiratory quality of life.” Past studies were limited by small sample sizes, as well as selection bias.

The authors of this study report, “We found that ECAC was associated with increased incidence of acute respiratory events on a follow-up in participants without COPD and with increased incidence of severe exacerbations in those with airflow obstruction.” Because this is a new finding, the researchers recommend that future studies should be done to find out if ECAC is part of a continuum of inflammation or if it causes respiratory decompensation.