title: Clinical characteristics and airway inflammation profile of COPD persistent sputum producers.
abstract: BACKGROUND
  COPD patients with chronic bronchitis include a subgroup with persistent sputum production on most or every day. We hypothesized that COPD patients with persistent sputum production have a different profile of airway inflammation, and more severe clinical characteristics.
  
  
  OBJECTIVE
  To compare the airway inflammation profile and clinical characteristics of COPD persistent and non-persistent sputum producers.
  
  
  METHODS
  COPD persistent sputum producers (n = 26) and non-persistent sputum producers (n = 26) underwent sputum induction and pulmonary function tests. Exacerbation history was recorded; the St. George's Respiratory Questionnaire, Modified Medical Research Council Dyspnoea scale and COPD Assessment Tool were completed. 33 COPD patients provided sputum for bacteriology.
  
  
  RESULTS
  Persistent sputum producers had lower post-bronchodilator FEV1% predicted (p = 0.01), diffusion capacity (p = 0.04), 6 min walk test distance (p = 0.05), and higher closing volume (p = 0.01), BODE index (p = 0.01), rate of bacterial colonization (p = 0.004) and exacerbations (p = 0.03) compared to non-persistent sputum producers. The mean SGRQ and CAT scores were higher in persistent sputum producers (p = 0.01 and 0.03 respectively). Sputum neutrophil and eosinophil total cell counts were higher in persistent sputum producers (p = 0.02 and 0.05 respectively). Sputum levels of eotaxin (p = 0.02), MCP-1 (p = 0.02), TNF-α (p = 0.03) and IL-6 (p = 0.05) were higher in persistent sputum producers.
  
  
  CONCLUSIONS
  COPD persistent sputum producers have more severe clinical characteristics and increased concentrations of some inflammatory mediators in the airways.
authors.forename: S
authors.initials: S
authors.lastname: Khurana
authors.forename: A
authors.initials: A
authors.lastname: Ravi
authors.forename: J
authors.initials: J
authors.lastname: Sutula
authors.forename: R
authors.initials: R
authors.lastname: Milone
authors.forename: R
authors.initials: R
authors.lastname: Williamson
authors.forename: J
authors.initials: J
authors.lastname: Plumb
authors.forename: J
authors.initials: J
authors.lastname: Vestbo
authors.forename: D
authors.initials: D
authors.lastname: Singh
mesh_terms: D000368:Aged; D001419:Bacteria / Q000302:isolation & purification; D029481:Bronchitis, Chronic / Q000209:etiology* / Q000378:metabolism / Q000382:microbiology / Q000503:physiopathology; D002452:Cell Count; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D012720:Severity of Illness Index; D013048:Specimen Handling / Q000379:methods; D013183:Sputum / Q000166:cytology / Q000378:metabolism* / Q000382:microbiology
chemical_list: D016207:Cytokines