Chronic bronchitis in 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.

METHODS: We analyzed data from subjects enrolled in the COPDGene® study. 1061 subjects with GOLD 2-4 disease were divided into two groups: chronic bronchitis (CB+) if subjects noted chronic cough and phlegm production for ≥3 months/year for 2 consecutive years, and no chronic bronchitis (CB-) if they did not.

RESULTS: 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=0.002), smoked more (57±30 vs. 52±25 pack-years, p=0.006), and had more current smokers (48% vs. 27%, p<0.0001). 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/patient, p<0.027), and more patients in the CB+ group reported a history of severe exacerbations (26.6% vs. 20.0%, p=0.024). There was no difference in %emphysema or %gas trapping, but the CB+ group had a higher mean segmental airway wall area percent (63.2±2.9% vs. 62.6±3.1%, p=0.013).

CONCLUSIONS: Chronic bronchitis in 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.