The association between chronic obstructive pulmonary disease and dementia: a population‐based retrospective cohort study

Background and purpose 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). Conclusion 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 .