Mucus dehydration may lead to reduced mucociliary clearance and symptoms of chronic bronchitis, according to new research published in the American Journal of Respiratory and Critical Care Medicine.

Researchers from the University of North Carolina at Chapel Hill found that mucus concentration was increased in patients with chronic bronchitis compared with healthy controls, and this correlated with disease severity.

“These data suggest airway mucus concentration could serve as a biomarker to complement the symptom-based diagnosis of [chronic bronchitis]”, the researchers wrote.

The 68 chronic bronchitis patients were aged an average of 59 years and had a smoking history of at least 20 pack-years; 44% were current smokers.

The average percent solids of bronchoscopically obtained mucus was increased about threefold in these patients, compared with in 29 nonsmoking healthy controls and in 34 smokers with no respiratory symptoms. The same was true for induced sputum, which the team noted would make a more practical diagnostic test.