Elsevier

Respiratory Medicine

Volume 108, Issue 3, March 2014, Pages 491-499
Respiratory Medicine

The clinical impact of non-obstructive chronic bronchitis in current and former smokers

https://doi.org/10.1016/j.rmed.2013.11.003Get rights and content
Under an Elsevier user license
open archive

Summary

Background

As the clinical significance of chronic bronchitis among smokers without airflow obstruction is unclear, we sought to determine morbidity associated with this disorder.

Methods

We examined subjects from the COPDGene study and compared those with FEV1/FVC ≥0.70, no diagnosis of asthma and chronic bronchitis as defined as a history of cough and phlegm production for ≥3 months/year for ≥2 years (NCB) to non-obstructed subjects without chronic bronchitis (CB-). Multivariate analysis was used to determine factors associated with and impact of NCB.

Results

We identified 597 NCB and 4283 CB- subjects. NCB participants were younger (55.4 vs. 57.2 years, p < 0.001) with greater tobacco exposure (42.9 vs. 37.8 pack-years, p < 0.001) and more often current smokers; more frequently reported occupational exposure to fumes (52.8% vs. 42.2%, p < 0.001), dust for ≥1 year (55.3% vs. 42.0%, p < 0.001) and were less likely to be currently working. NCB subjects demonstrated worse quality-of-life (SGRQ 35.6 vs. 15.1, p < 0.001) and exercise capacity (walk distance 415 vs. 449 m, p < 0.001) and more frequently reported respiratory “flare-ups” requiring treatment with antibiotics or steroids (0.30 vs. 0.10 annual events/subject, p < 0.001) prior to enrollment and during follow-up (0.34 vs. 0.16 annual events/subject, p < 0.001). In multivariate analysis, current smoking, GERD, sleep apnea and occupational exposures were significantly associated with NCB.

Conclusions

While longitudinal data will be needed to determine whether NCB progresses to COPD, NCB patients have poorer quality-of-life, exercise capacity and frequent respiratory events. Beyond smoking cessation interventions, further research is warranted to determine the benefit of other therapeutics in this population.

Clinical Trials Registration # NCT00608764 (http://clinicaltrials.gov/show/NCT00608764).

Link to study protocol: http://www.copdgene.org/sites/default/files/COPDGeneProtocol-5-0_06-19-2009.pdf.

Keywords

Cough
Quality of life
Gastroesophageal reflux
Occupational exposure
GERD
Tobacco

Cited by (0)

Prior abstract presentation: Presented as an abstract at the American Thoracic Society International Conference, San Francisco 2012.

1

Co-senior authors.