title: Sputum microbiology predicts health status in COPD.
abstract: BACKGROUND
  Spontaneous sputum production occurs in a subset of COPD patients; however, its clinical relevance has not been established. Differences in health status and clinical outcomes between patients with and without positive sputum cultures are unknown.
  
  
  OBJECTIVE
  To compare clinical characteristics and health status of spontaneous sputum producers with a positive culture (SC+) and negative culture (SC-) with nonsputum producers (NP) in a cohort of COPD patients referred for pulmonary rehabilitation.
  
  
  METHODS
  In total, 518 clinically stable patients with mild-to-very severe COPD were recruited (mean age: 64.1±9.1 years, 55.6% males, forced expiratory volume in 1 second 48.6%±20.0% predicted). Health status was measured using COPD Assessment Test, St George's Respiratory Questionnaire, and the Clinical COPD Questionnaire. Symptoms of anxiety and depression were assessed using the Hospital Anxiety and Depression Scale. Exercise capacity was measured using the 6-minute walking distance. Spontaneously expectorated sputum was cultured for microbiology.
  
  
  RESULTS
  Almost one-third of patients spontaneously produced sputum (n=164, 31.7%). Despite comparable lung function, SC+ reported more frequent exacerbations than NP (≥2 exacerbations <1 year: 43 [81.1%] vs 179 [50.6%],P<0.001). COPD Assessment Test total score and the Clinical COPD Questionnaire total score were significantly worse in SC+ than NP (23.9±6.1 vs 21.1±6.7,P=0.012; 3.1±1.0 vs 2.5±1.0,P=0.002; respectively). Hospital Anxiety and Depression Scale-D score was significantly higher in SC+ than NP (8.7±4.1 vs 7.2±4.3,P=0.046).
  
  
  CONCLUSIONS
  Spontaneous sputum production is common in COPD. Particularly, patients with positive cultures have worse health status and more symptoms of depression. Impact on disease progression and long-term outcomes remain to be established.
  
  
  BACKGROUND
  NTR3416, registered at www.trialregister.nl.
authors.affiliation: Department of Research and Education, CIRO, Horn, the Netherlands; Department of Respiratory Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, the Netherlands.
authors.forename: Dionne Cw
authors.initials: DC
authors.lastname: Braeken
authors.affiliation: Department of Research and Education, CIRO, Horn, the Netherlands.
authors.forename: Sarah
authors.initials: S
authors.lastname: Houben-Wilke
authors.affiliation: Department of Research and Education, CIRO, Horn, the Netherlands.
authors.forename: Dionne E
authors.initials: DE
authors.lastname: Smid
authors.affiliation: Department of Respiratory Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, the Netherlands.
authors.forename: Gernot Gu
authors.initials: GG
authors.lastname: Rohde
authors.affiliation: Department of Respiratory Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, the Netherlands.
authors.forename: Jesse Jc
authors.initials: JJ
authors.lastname: Drijkoningen
authors.affiliation: Department of Research and Education, CIRO, Horn, the Netherlands; Department of Respiratory Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, the Netherlands.
authors.forename: Emiel Fm
authors.initials: EF
authors.lastname: Wouters
authors.affiliation: Department of Research and Education, CIRO, Horn, the Netherlands.
authors.forename: Martijn A
authors.initials: MA
authors.lastname: Spruit
authors.affiliation: Department of Research and Education, CIRO, Horn, the Netherlands; Department of Respiratory Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, the Netherlands.
authors.forename: Frits Me
authors.initials: FM
authors.lastname: Franssen
mesh_terms: D000368:Aged; D018450:Disease Progression; D017079:Exercise Tolerance; D005260:Female; D005541:Forced Expiratory Volume; D006304:Health Status; D006801:Humans; D008168:Lung / Q000382:microbiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D011237:Predictive Value of Tests; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000382:microbiology* / Q000503:physiopathology / Q000628:therapy; D012141:Respiratory Tract Infections / Q000175:diagnosis / Q000382:microbiology* / Q000503:physiopathology / Q000628:therapy; D012307:Risk Factors; D012720:Severity of Illness Index; D013183:Sputum / Q000382:microbiology*; D011795:Surveys and Questionnaires; D000070857:Walk Test
keywords: COPD; health status; microbiology; pulmonary rehabilitation; sputum