Potentially High-Risk Antipsychotic Use in People With Dementia: A National Data Linkage Study.

Objectives: To investigate the prevalence of and sociodemographic factors associated with potentially high-risk antipsychotic use in people living with dementia in Australia.

Design: Retrospective cross-sectional study using national linked data from the 2021 Census and the Pharmaceutical Benefits Scheme.

Setting and participants: All people ≥65 years of age who responded to the 2021 Census, self-reported a diagnosis of dementia and/or were dispensed an acetylcholinesterase inhibitor or memantine, and purchased ≥1 antipsychotic subsidized by the Pharmaceutical Benefits Scheme between August 1, 2021, and October 31, 2021, were included.

Methods: Four measures of potentially high-risk antipsychotic use were assessed: possible drug-drug interactions, possible drug-disease interactions (DDSIs) (ie, stroke or diabetes), concomitant psychotropic medication (CPM), and prolonged duration of use (ie, ≥4 prescriptions in the 6 months from August 1, 2021). Factors associated with each measure were identified by logistic regression models.

Results: Of the 22,710 individuals using at least 1 antipsychotic, 9947 (43.8%) were using risperidone. A total of 19,576 people (86.2%) had ≥1 measure of high-risk use. The most common measure was CPM (n = 17,560, 77.3%), followed by drug-drug interaction (n = 7059, 31.1%), DDSI (n = 5125, 22.6%), and prolonged duration of use (n = 2129, 9.4%). The factors of ≥75 years of age, higher educational attainment, and living in a remote area were associated with lower odds of having ≥1 measure, whereas multimorbidity was associated with increased likelihood. Residing in nonprivate dwellings and having multiple prescribers were associated with higher odds of having multiple measures, except for DDSI. Culturally and linguistically diverse populations had higher odds of DDSI but lower odds of CPM.

Conclusions and implications: Achieving quality use of antipsychotics in individuals with dementia remains challenging, with almost 9 of 10 antipsychotic users having at least 1 measure of high-risk use. Future research should investigate strategies to optimize antipsychotic use in people living with dementia and target subgroups at higher risk.