Abstract
Background
Most studies assessing the effect of central nervous system (CNS)-acting medicines
on cognitive disturbances have focused on the use of individual medicines. The impact
on cognitive function when another CNS-acting medicine is added to a patient's treatment
regimen is not well known.
Objective
To determine risk of hospitalization for confusion, delirium, or dementia in older
people associated with increasing numbers of CNS-acting medicines taken concurrently,
as well as the number of standard doses taken each day (measured as defined daily
doses).
Design
Retrospective cohort study, from July 2011 to June 2012, using health claims data.
Setting
Australian veteran population.
Participants
A total of 74,321 community-dwelling individuals aged 65 years and over, who were
dispensed at least 1 CNS-acting medicine in the year before study entry. Patients
with prior hospitalization for confusion or delirium, and those with dementia or receiving
palliative care, were excluded.
Main outcome measure
Hospitalization for confusion, delirium, or dementia.
Results
Over the 1-year study period, 401 participants were hospitalized with confusion, delirium,
or dementia. Adjusted analyses showed the risk of hospitalization was 2.4 times greater
with the use of 2 CNS-acting medicines compared with no use [incident rate ratio (IRR)
2.39, 95% confidence interval (CI) 1.79–3.19, P < .001], and more than 19 times greater when 5 or more CNS-acting medicines were
taken concurrently (IRR 19.35, 95% CI 11.10–33.72, P < .001). Similarly, the risk of hospitalization was significantly increased among
patients taking between 1.0 and 1.9 standard doses per day (IRR 2.64, 95% CI 1.99–3.50,
P < .001) and between 2.0 and 2.9 standard doses per day (IRR 3.43, 95% CI 2.07–5.69,
P < .001) compared with no use.
Conclusions
Use of multiple CNS-acting medicines or higher doses is associated with an increased
risk of hospitalization for confusion, delirium, or dementia. Health care professionals
need to be alert to the contribution of CNS-acting medicines among patients presenting
with confusion or delirium and consider strategies to reduce treatment burden where
possible.
Keywords
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Article info
Publication history
Published online: March 24, 2016
Footnotes
This research was funded by the Australian Government Department of Veterans' Affairs (DVA) as part of the delivery of the Veterans' Medicines Advice and Therapeutics Education Services (Veterans' MATES) project. DVA did not have any role in the design and conduct of the study; collection, management, analysis or interpretation of the data. DVA reviewed this manuscript before submission but played no role in the preparation of the manuscript, or decision to submit the manuscript for publication. The authors are employed on the Veterans' MATES program. There are no other conflicts of interest to declare.
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© 2016 AMDA - The Society for Post-Acute and Long-Term Care Medicine.
