Airway Disorder Relatively Common Among Smokers Associated With Worse Respiratory Quality of Life

Smoking
A relatively common airway disorder among current and former smokers is linked to increase in shortness of breath and coughing, according to a recent study. Pixabay

New research published in JAMA examines whether an airway disorder associated with chronic obstructive pulmonary disease (COPD) — whose most significant risk factor is long-term cigarette smoking — is linked to respiratory morbidity in current and former smokers independent of underlying lung disease.

Expiratory respiratory quality of life (ECAC) is a relatively common airway disorder among current and former smokers. It occurs when the lateral circumference of the airway decreases by at least 50 percent during exhalation. The condition is increasingly recognized in the adult population, especially in association with cigarette smoking and COPD. However, its prevalence and clinical significance are unknown.

“ECAC has long been recognized to be associated with respiratory symptoms including chronic cough, dyspnea, stridor, and wheezing resistant to corticosteroids; impaired clearance of secretions; and respiratory failure. However, these symptoms are nonspecific and have been variously ascribed to the underlying diseases such as chronic bronchitis and emphysema,” researchers wrote.

Researchers collected and analyzed data from 8,820 study participants, of whom 3,856 had COPD and 4,964 didn’t, for an average of four years. There were 443 cases of ECAC in the group; the prevalence was higher in people with COPD (nearly 6 percent) than in those without COPD (4 percent). Fifty-two percent of the cohort were active smokers.  

After adjusting for demographics and structural lung disease, researchers found that compared to those withouth ECAC, people with the airway disorder had worse scores on measures of respiratory quality of life and shortness of breath.

Among those with COPD, the airway disorder was not associated with total number of exacerbations, or respiratory worsening, such as increase in shortness of breath or coughing, lasting at least 48 hours and requiring use of either antibiotics or systemic steroids. However, it was associated with a higher incidence of severe exacerbations, which are respiratory events that result in hospitalization. Surprisingly, among people without lung disease, the ECAC was associated with increased frequency of both total number of exacerbations and severe exacerbations requiring hospitalization.

“Although ECAC may be a marker of poorer outcomes in patients with COPD, that ECAC is associated with increased frequency of mild-moderate and severe respiratory events in those without airflow obstruction is also noteworthy,” the study authors added.

More research is needed to determine whether ECAC is a marker for future respiratory events, they said.

Source: Bhatt S, Terry N, Nath H, et al. Association Between Expiratory Central Airway Collapse and Respiratory Outcomes Among Smokers. JAMA. 2016.

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