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

Carlos H Martinez, Victor Kim, Yahong Chen, Ella A Kazerooni, Susan Murray, Gerard J Criner, Jeffrey L Curtis, Elizabeth A Regan, Emily Wan, Craig P Hersh, Edwin K Silverman, James D Crapo, Fernando J Martinez, Meilan K Han, COPDGene Investigators, Edwin Jacques Rudolph van Beek

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

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.

Original languageEnglish
Pages (from-to)491-9
Number of pages9
JournalRespiratory Medicine
Volume108
Issue number3
DOIs
Publication statusPublished - Mar 2014

Keywords / Materials (for Non-textual outputs)

  • Aged
  • Aged, 80 and over
  • Bronchitis, Chronic
  • Cough
  • Exercise Tolerance
  • Female
  • Humans
  • Male
  • Middle Aged
  • Morbidity
  • Occupational Exposure
  • Quality of Life
  • Questionnaires
  • Risk Factors
  • Smoking

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