title: Relationship between gastroesophageal reflux disease and COPD in UK primary care.
abstract: BACKGROUND
  Gastroesophageal reflux symptoms may be more common in patients with COPD than in control subjects. The aim of this study was to investigate the relationship between diagnoses of COPD and gastroesophageal reflux disease (GERD) in primary care.
  
  
  METHODS
  We used the UK General Practice Research Database to identify a cohort of patients with a first diagnosis of GERD (n = 4,391) and another cohort of patients with a first diagnosis of COPD (n = 1,628) during 1996, which we compared with age-matched and sex-matched comparison cohorts without either diagnosis. We calculated the incidence of a GERD diagnosis among the patients with COPD and control subjects, and of a COPD diagnosis among the patients with GERD and control subjects. We also calculated the relative risk (RR) estimates of these diagnoses using the Mantel-Haenszel test. Risks associated with medication use, comorbidities, and demographic and lifestyle factors were examined using a nested case-control analysis.
  
  
  RESULTS
  During the 5-year follow-up, the RR of an incident COPD diagnosis in patients with a diagnosis of GERD was 1.17 (95% confidence interval [CI], 0.91 to 1.49), while the RR of an incident GERD diagnosis among patients with a diagnosis of COPD was 1.46 (95% CI, 1.19 to 1.78). A COPD diagnosis was associated with current or former smoking, prior diagnosis of asthma, or the use of asthma medication. A GERD diagnosis was associated with a prior diagnosis of ischemic heart disease.
  
  
  CONCLUSIONS
  Patients with a diagnosis of COPD are at a significantly increased risk of a diagnosis of GERD compared with individuals with no COPD diagnosis.
authors.affiliation: Spanish Centre for Pharmacoepidemiological Research, Madrid, Spain. Electronic address: lagarcia@ceife.es.
authors.forename: Luis A
authors.initials: LA
authors.lastname: García Rodríguez
authors.affiliation: Spanish Centre for Pharmacoepidemiological Research, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Ruigómez
authors.affiliation: Spanish Centre for Pharmacoepidemiological Research, Madrid, Spain.
authors.forename: Elisa
authors.initials: E
authors.lastname: Martín-Merino
authors.affiliation: AstraZeneca R&D, Mölndal, Sweden.
authors.forename: Saga
authors.initials: S
authors.lastname: Johansson
authors.affiliation: AstraZeneca R&D, Mölndal, Sweden.
authors.forename: Mari-Ann
authors.initials: MA
authors.lastname: Wallander
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care / Q000706:statistics & numerical data*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology*; D012307:Risk Factors; D006113:United Kingdom