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Respir Med. 2014 Mar;108(3):491-9. doi: 10.1016/j.rmed.2013.11.003. Epub 2013 Nov 15.

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

Author information

1
Pulmonary & Critical Care Division, University of Michigan Health System, Ann Arbor, MI, USA. Electronic address: carlosma@umich.edu.
2
Division of Pulmonary and Critical Care, Temple University School of Medicine, Philadelphia, PA, USA.
3
Respiratory Department, Peking University Third Hospital, Beijing, China.
4
Department of Radiology, University of Michigan, Ann Arbor, MI, USA.
5
School of Public Health, University of Michigan, Ann Arbor, MI, USA.
6
Pulmonary & Critical Care Division, University of Michigan Health System, Ann Arbor, MI, USA; Medicine Service, VA Healthcare System, Ann Arbor, MI, USA.
7
Department of Medicine, National Jewish Medical and Research Center, Denver, CO, USA.
8
Channing Division of Network Medicine and Pulmonary and Critical Care Division, Brigham and Women's Hospital, Boston, MA, USA.
9
Pulmonary & Critical Care Division, University of Michigan Health System, Ann Arbor, MI, USA.

Abstract

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; GERD; Gastroesophageal reflux; Occupational exposure; Quality of life; Tobacco

PMID:
24280543
PMCID:
PMC3943716
DOI:
10.1016/j.rmed.2013.11.003
[Indexed for MEDLINE]
Free PMC Article

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