Chronic bronchitis (CB) in patients with COPD is associated with an accelerated lung
function decline and an increased risk of respiratory infections. Despite its clinical
significance, the chronic bronchitic phenotype in COPD remains poorly defined.
We analyzed data from subjects enrolled in the Genetic Epidemiology of COPD (COPDGene)
Study. A total of 1,061 subjects with GOLD (Global Initiative for Chronic Obstructive
Lung Disease) stage II to IV were divided into two groups: CB (CB+) if subjects noted
chronic cough and phlegm production for ≥ 3 mo/y for 2 consecutive years, and no CB
(CB-) if they did not.
There were 290 and 771 subjects in the CB+ and CB- groups, respectively. Despite similar
lung function, the CB+ group was younger (62.8 ± 8.4 vs 64.6 ± 8.4 years, P = .002),
smoked more (57 ± 30 vs 52 ± 25 pack-years, P = .006), and had more current smokers
(48% vs 27%, P < .0001). A greater percentage of the CB+ group reported nasal and
ocular symptoms, wheezing, and nocturnal awakenings secondary to cough and dyspnea.
History of exacerbations was higher in the CB+ group (1.21 ± 1.62 vs 0.63 ± 1.12 per
patient, P < .027), and more patients in the CB+ group reported a history of severe
exacerbations (26.6% vs 20.0%, P = .024). There was no difference in percent emphysema
or percent gas trapping, but the CB+ group had a higher mean percent segmental airway
wall area (63.2% ± 2.9% vs 62.6% ± 3.1%, P = .013).
CB in patients with COPD is associated with worse respiratory symptoms and higher
risk of exacerbations. This group may need more directed therapy targeting chronic
mucus production and smoking cessation not only to improve symptoms but also to reduce
risk, improve quality of life, and improve outcomes.
ClinicalTrials.gov; No.: NCT00608764; URL: www.clinicaltrials.gov.