title: The association between chronic obstructive pulmonary disease and dementia: a population-based retrospective cohort study.
abstract: OBJECTIVE
  Chronic obstructive pulmonary disease (COPD) is frequently associated with various comorbidities. However, the proportion of COPD patients with dementia has not been adequately examined. This retrospective cohort study investigated the association between COPD and dementia by using a nationwide population-based database in Taiwan.
  
  
  METHODS
  Data were retrieved from the Taiwanese National Health Insurance Research Database and analyzed using multivariate Cox proportional hazards regression models to assess the effects of COPD on the risk of dementia after adjusting for demographic characteristics and comorbidities.
  
  
  RESULTS
  The COPD cohort exhibited a higher prevalence of diabetes, hypertension, coronary artery disease, head injury and depression at baseline than did the non-COPD cohort (P < 0.0001). After adjusting for covariates, the COPD patients exhibited a 1.27-fold higher risk of developing dementia (hazard ratio 1.27, 95% confidence interval 1.20-1.36). The incidence rate was higher in patients with frequent acute exacerbations than in the non-COPD patients regardless of whether a hospital admission or emergency room visit was required (hazard ratio 196.8 vs. 41.7, 95% confidence intervals 145.9-265.5 and 22.3-78.0).
  
  
  CONCLUSIONS
  This study shows that COPD is associated with a subsequent higher risk of dementia after adjusting for comorbidities. Specifically, the association between COPD and dementia is greater in patients with more frequent acute exacerbation events of COPD.
authors.affiliation: Graduate Institute of Clinical Medical Science, College of Medicine, China Medical University, Taichung, Taiwan; Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan.
authors.forename: W-C
authors.initials: WC
authors.lastname: Liao
authors.forename: C-L
authors.initials: CL
authors.lastname: Lin
authors.forename: S-N
authors.initials: SN
authors.lastname: Chang
authors.forename: C-Y
authors.initials: CY
authors.lastname: Tu
authors.forename: C-H
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000368:Aged; D015897:Comorbidity; D003704:Dementia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D012189:Retrospective Studies; D012306:Risk; D013624:Taiwan / Q000453:epidemiology
keywords: acute exacerbation; chronic obstructive pulmonary disease; dementia