Cholinesterase inhibitors and adverse pulmonary events in older people with chronic obstructive pulmonary disease and concomitant dementia: a population-based, cohort study.

Background: Cholinesterase inhibitors (ChEIs) are a mainstay treatment for individuals with dementia. ChEIs may worsen airflow obstruction because of their pro-cholinergic properties.
Objective: The objective of this study was to evaluate the risk of serious pulmonary complications in the elderly with concomitant chronic obstructive pulmonary disease (COPD) and dementia who were receiving ChEIs.
Methods: This was a population-based, cohort study conducted between 2003 and 2010 in residents of Ontario, Canada. Subjects were over the age of 66 years and had concomitant dementia and COPD, identified using linked administrative databases. Exposure to ChEIs was determined using a drug benefits database. The primary outcome was an emergency room (ER) visit or hospitalization for COPD. The risk difference at 60 days and the relative risk (RR) for study outcomes were estimated in the propensity score-matched sample.
Results: Of 266,840 individuals with COPD, 45,503 had a concomitant diagnosis of dementia. A total of 7166 unexposed subjects were matched to subjects newly exposed to ChEIs. New users of ChEIs were not at significantly higher risk of ER visits or hospitalizations for COPD (RR 0.90; 95% CI 0.76, 1.07) or COPD exacerbations (RR 1.02; 95% CI 0.91, 1.15). Furthermore, ER visits for any respiratory diagnoses were not increased among new users of ChEIs (RR 1.02; 95% CI 0.87, 1.19) when compared with non-users. Sub-group analyses were consistent with the main analysis.
Conclusions: In a large cohort of elderly individuals with COPD and dementia, new users of ChEIs had a similar risk for adverse pulmonary outcomes as those who were not receiving ChEIs.