title: Gastro-esophageal reflux disease and exacerbations in chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  We tested the hypothesis that gastro-esophageal reflux disease is a risk factor for exacerbations in individuals with chronic obstructive pulmonary disease (COPD).
  
  
  METHODS
  Among 9622 participants in the Copenhagen City Heart Study, we identified 1259 individuals with COPD and information on gastro-esophageal reflux disease and the regular use of acid inhibitory treatment. These individuals were followed for 5 years with regard to medically treated COPD exacerbations, which we defined as a short course treatment with oral corticosteroids alone or in combination with antibiotics. We applied a multivariable Cox regression analysis with adjustment for well-established risk factors associated with COPD exacerbations or gastro-esophageal reflux disease, including COPD severity, and symptoms.
  
  
  RESULTS
  Individuals with COPD and gastro-esophageal reflux disease had more chronic bronchitis (31 vs 21%, P = 0.004), more breathlessness (39 vs 22%, P < 0.001), and more of them had a history of respiratory infections (6.8 vs 1.4%, P < 0.001) than individuals with COPD but without gastro-esophageal reflux disease. Among individuals with COPD and gastro-esophageal reflux disease, those who did not use acid inhibitory treatment regularly had an increased risk of COPD exacerbations during follow-up, hazards ratio (HR): HR = 2.7 (1.3-5.4, P = 0.006). Individuals with gastro-esophageal reflux disease, using acid inhibitory treatment regularly did not have an increased risk of exacerbations, HR = 1.2 (0.6-2.7, P = 0.63).
  
  
  CONCLUSIONS
  Gastro-esophageal reflux disease was associated with an increased risk of medically treated exacerbations of COPD, but only in those individuals who did not use acid inhibitory treatment regularly.
authors.affiliation: Department of Respiratory Medicine, Odense University Hospital, Odense, Denmark; Institute of Clinical Research, University of Southern Denmark, Odense, Denmark; The Copenhagen City Heart Study, Frederiksberg Hospital, Copenhagen, Denmark; The Copenhagen General Population Study, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Truls S
authors.initials: TS
authors.lastname: Ingebrigtsen
authors.forename: Jacob L
authors.initials: JL
authors.lastname: Marott
authors.forename: Jørgen
authors.initials: J
authors.lastname: Vestbo
authors.forename: Børge G
authors.initials: BG
authors.lastname: Nordestgaard
authors.forename: Jesper
authors.initials: J
authors.lastname: Hallas
authors.forename: Peter
authors.initials: P
authors.lastname: Lange
mesh_terms: D000368:Aged; D000863:Antacids / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D003718:Denmark / Q000453:epidemiology; D018450:Disease Progression; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D016016:Proportional Hazards Models; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D012129:Respiratory Function Tests / Q000379:methods; D012307:Risk Factors; D012720:Severity of Illness Index
chemical_list: D000863:Antacids; D000900:Anti-Bacterial Agents; D005938:Glucocorticoids
keywords: acid inhibitory treatment; chronic obstructive pulmonary disease; reflux