Author(s):
C. H.
Martinez, V.
Kim, Y.
Chen, E. A.
Kazerooni, S.
Murray, G. J.
Criner, J. L.
Curtis, E. A.
Regan, E.
Wan, C. P.
Hersh, E. K.
Silverman, J. D.
Crapo, F. J.
Martinez, M. K.
Han
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.
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ISBN:
1532-3064 (Electronic)0954-6111 (Linking)
Publication Year:
2013
Periodical:
Respir Med
Periodical Number:
Volume:
Pages:
Author Address:
Pulmonary & Critical Care Division, University of Michigan Health System, Ann Arbor, MI, USA. Electronic address: carlosma@umich.edu.