Poisonings in Older People with Dementia: A Systematic Scoping Review and Meta-Analysis

Background: Older people with dementia are at a particularly high risk of poisonings and their subsequent harms. Objective: This review aimed to describe the key agents, incidence, risk factors, and disposition of poisonings in people with dementia reported in the literature. Methods: Medline, Embase, CINAHL, and PsycINFO databases were searched from 1 September 2001 to 1 September 2021. Terms for dementia, poisonings, and older adults formed the search concepts. Quantitative studies published in English, describing poisonings in older people with dementia, including Alzheimer's disease, were included. Two investigators independently assessed articles for eligibility and extracted relevant data. A meta-analysis of the incidence of poisonings in people with dementia across studies was performed. Results: Of 4,579 articles, 18 were included for final synthesis. Nervous system medications were implicated in over half of all medicinal poisonings, with anti-dementia agents, benzodiazepines, and opioids the most common classes. The non-medicinal agents frequently associated with poisonings were personal care and household products. The yearly incidence of poisoning varied across definitions of poisoning from 3% for International Classification of Disease-defined poisonings to 43% for adverse drug event-defined poisonings. Several risk factors were identified, including multimorbidity, psychotropic medication use, and living in residential care. Where described, up to one in five poisonings resulted in hospitalisation and in death. Conclusions: Poisonings are common in people with dementia, involving commonly prescribed medications or easily accessible substances. Given the significant outcomes associated, further research is required to better understand these poisonings and improve public health strategies to reduce the occurrence of this preventable harm.