title: Subjects with COPD and productive cough have an increased risk for exacerbations and death.
abstract: BACKGROUND
  Chronic bronchitis is related to worse general health status, exacerbations and mortality among subjects with COPD. Also less longstanding cough and phlegm may be related to worse prognosis in COPD but this has rarely been evaluated in population-based studies.
  
  
  OBJECTIVE
  To evaluate the relationship between productive cough, exacerbations and mortality among subjects with and without COPD.
  
  
  METHODS
  All subjects with COPD (n = 993) were identified together with sex- and age matched reference subjects without obstructive lung function impairment from four population-based cohorts in 2002-04. Baseline spirometry and structured interview including data on exacerbations last 12 months were used in this study (n = 1986) together with mortality data collected until February 2012.
  
  
  RESULTS
  Productive cough was more common in COPD than non-COPD (42.8 vs. 23.5%, p < 0.001), more common in men than women, but associated to exacerbations in both sexes. COPD-subjects with productive cough had the highest risk for exacerbations in both sexes and they had a significantly increased risk for death (HR 1.48, 95% CI 1.13-1.94) also when adjusted for sex, age, BMI, smoking habits and heart disease.
  
  
  CONCLUSIONS
  Productive cough was common and increased the risk for exacerbations in both sexes, in both COPD and non-COPD. COPD-subjects with productive cough had the highest risk for exacerbations and a significantly higher risk for death also after adjustment for common risk factors.
authors.affiliation: Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden. Electronic address: anne.lindberg@algmed.se.
authors.forename: Anne
authors.initials: A
authors.lastname: Lindberg
authors.affiliation: Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden.
authors.forename: Sami
authors.initials: S
authors.lastname: Sawalha
authors.affiliation: Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine, The OLIN Unit, Umeå University, Sweden.
authors.forename: Linnea
authors.initials: L
authors.lastname: Hedman
authors.affiliation: Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden.
authors.forename: Lars-Gunnar
authors.initials: LG
authors.lastname: Larsson
authors.affiliation: Department of Internal Medicine/Krefting Research Centre, Sahlgrenska Academy, University of Gothenburg, Sweden.
authors.forename: Bo
authors.initials: B
authors.lastname: Lundbäck
authors.affiliation: Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine, The OLIN Unit, Umeå University, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Rönmark
mesh_terms: D000328:Adult; D000368:Aged; D029481:Bronchitis, Chronic / Q000150:complications / Q000401:mortality; D016022:Case-Control Studies; D003371:Cough / Q000209:etiology / Q000401:mortality*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis / Q000401:mortality*; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects / Q000401:mortality; D013548:Sweden / Q000453:epidemiology
keywords: COPD; Epidemiology; Exacerbations; Mortality; Productive cough