title: Productivity losses in chronic obstructive pulmonary disease: a population-based survey.
abstract: OBJECTIVE
  We aimed to estimate incremental productivity losses (sick leave and disability) of spirometry-defined chronic obstructive pulmonary disease (COPD) in a population-based sample and in hospital-recruited patients with COPD. Furthermore, we examined predictors of productivity losses by multivariate analyses.
  
  
  METHODS
  We performed four quarterly telephone interviews of 53 and 107 population-based patients with COPD and controls, as well as 102 hospital-recruited patients with COPD below retirement age. Information was gathered regarding annual productivity loss, exacerbations of respiratory symptoms and comorbidities. Incremental productivity losses were estimated by multivariate quantile median regression according to the human capital approach, adjusting for sex, age, smoking habits, education and lung function. Main effect variables were COPD/control status, number of comorbidities and exacerbations of respiratory symptoms.
  
  
  RESULTS
  Altogether 55%, 87% and 31% of population-based COPD cases, controls and hospital patients, respectively, had a paid job at baseline. The annual incremental productivity losses were 5.8 (95% CI 1.4 to 10.1) and 330.6 (95% CI 327.8 to 333.3) days, comparing population-recruited and hospital-recruited patients with COPD to controls, respectively. There were significantly higher productivity losses associated with female sex and less education. Additional adjustments for comorbidities, exacerbations and FEV1% predicted explained all productivity losses in the population-based sample, as well as nearly 40% of the productivity losses in hospital-recruited patients.
  
  
  CONCLUSIONS
  Annual incremental productivity losses were more than 50 times higher in hospital-recruited patients with COPD than that of population-recruited patients with COPD. To ensure a precise estimation of societal burden, studies on patients with COPD should be population-based.
authors.affiliation: Department of Thoracic Medicine , Haukeland University Hospital , Bergen , Norway.
authors.forename: Marta
authors.initials: M
authors.lastname: Erdal
authors.affiliation: Centre for Clinical Research, Haukeland University Hospital , Bergen , Norway.
authors.forename: Ane
authors.initials: A
authors.lastname: Johannessen
authors.affiliation: Department of Economics , University of Bergen , Bergen , Norway.
authors.forename: Jan Erik
authors.initials: JE
authors.lastname: Askildsen
authors.affiliation: Department of Thoracic Medicine , Haukeland University Hospital , Bergen , Norway ; Department of Clinical Science , University of Bergen , Norway.
authors.forename: Tomas
authors.initials: T
authors.lastname: Eagan
authors.affiliation: Department of Clinical Science , University of Bergen , Norway.
authors.forename: Amund
authors.initials: A
authors.lastname: Gulsvik
authors.affiliation: Department of Thoracic Medicine , Haukeland University Hospital , Bergen , Norway ; Department of Clinical Science , University of Bergen , Norway.
authors.forename: Rune
authors.initials: R
authors.lastname: Grønseth
keywords: COPD epidemiology; Health Economist