title: Spirometry, questionnaire and electronic medical record based COPD in a population survey: Comparing prevalence, level of agreement and associations with potential risk factors.
abstract: BACKGROUND
  COPD-diagnosis is confirmed by post-bronchodilator (BD) spirometry. However, epidemiological studies often rely on pre-BD spirometry, self-reports, or medical records. This population-based study aims to determine COPD-prevalence based on four different operational definitions and their level of agreement, and to compare associations between COPD-definitions and risk factors.
  
  
  METHODS
  COPD-prevalence in 1,793 adults from the general Dutch population (aged 18-70 years) was assessed based on self-reported data, Electronic Medical Records (EMR), and post-BD spirometry: using the FEV1/FVC below the lower limit of normal (LLN) and GOLD fixed cut-off (FEV1/FVC <0.70). Using spirometry as a reference, sensitivity was calculated for self-reported and EMR-based COPD. Associations between COPD and known risk factors were assessed with logistic regression. Data were collected as part of the cross-sectional VGO study (Livestock Farming and Neighboring Residents' Health Study).
  
  
  RESULTS
  The highest prevalence was found based on spirometry (GOLD: 10.9%, LLN: 5.9%), followed by self-report (4.6%) and EMR (2.9%). Self-reported or EMR-based COPD identified less than 30% of all COPD-cases based on spirometry. The direction of association between known risk factors and COPD was similar across the four definitions, however, magnitude and significance varied. Especially indicators of allergy were more strongly associated with self-reported COPD compared to the other definitions.
  
  
  CONCLUSIONS
  COPD-prevalence varied depending on the used definition. A substantial number of subjects with spirometry-based COPD cannot be identified with questionnaires or medical records which can cause underestimation of COPD-prevalence. The influence of the different COPD-definitions on associations with known risk factors was limited.
authors.affiliation: Institute for Risk Assessment Sciences, IRAS, Utrecht University, Utrecht, The Netherlands.|Netherlands Institute for Health Services Research, NIVEL, Utrecht, The Netherlands.
authors.forename: Floor
authors.identifier: http://orcid.org/0000-0002-3297-4403
authors.initials: F
authors.lastname: Borlée
authors.affiliation: Netherlands Institute for Health Services Research, NIVEL, Utrecht, The Netherlands.
authors.forename: C Joris
authors.initials: CJ
authors.lastname: Yzermans
authors.affiliation: Institute for Risk Assessment Sciences, IRAS, Utrecht University, Utrecht, The Netherlands.
authors.forename: Esmeralda
authors.initials: E
authors.lastname: Krop
authors.affiliation: Netherlands Expertise Centre for Occupational Respiratory Disorders, Utrecht, The Netherlands.
authors.forename: Bernadette
authors.initials: B
authors.lastname: Aalders
authors.affiliation: Netherlands Expertise Centre for Occupational Respiratory Disorders, Utrecht, The Netherlands.
authors.forename: Jos
authors.initials: J
authors.lastname: Rooijackers
authors.affiliation: Netherlands Institute for Health Services Research, NIVEL, Utrecht, The Netherlands.
authors.forename: Jan-Paul
authors.initials: JP
authors.lastname: Zock
authors.affiliation: Netherlands Institute for Health Services Research, NIVEL, Utrecht, The Netherlands.
authors.forename: Christel E
authors.initials: CE
authors.lastname: van Dijk
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Centre for Infectious Disease Control, Bilthoven, The Netherlands.
authors.forename: Catharina B M
authors.initials: CB
authors.lastname: Maassen
authors.affiliation: Netherlands Institute for Health Services Research, NIVEL, Utrecht, The Netherlands.|Department of General Practice & Elderly Care Medicine/EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: François
authors.initials: F
authors.lastname: Schellevis
authors.affiliation: Institute for Risk Assessment Sciences, IRAS, Utrecht University, Utrecht, The Netherlands.
authors.forename: Dick
authors.initials: D
authors.lastname: Heederik
authors.affiliation: Institute for Risk Assessment Sciences, IRAS, Utrecht University, Utrecht, The Netherlands.
authors.forename: Lidwien A M
authors.initials: LA
authors.lastname: Smit
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D057286:Electronic Health Records; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D012307:Risk Factors; D057566:Self Report; D012720:Severity of Illness Index; D013147:Spirometry; D011795:Surveys and Questionnaires; D014797:Vital Capacity / Q000502:physiology