The prevalence and incidence of delirium superimposed on dementia in community settings: A systematic review and meta-analysis.

Delirium superimposed on dementia (DSD) is a serious condition causing poor outcomes. There is a significant gap in understanding the epidemiology in community settings. This systematic review aimed to estimate the prevalence and incidence of delirium in community-dwelling people with dementia. Medline, Embase, PsychINFO, Scopus, Web of Science, CINAHL, and Cochrane databases were searched from inception to January 6, 2025. Articles published in peer-reviewed journals that focused on the prevalence, incidence, or occurrence of DSD were included. Twenty-seven studies met the inclusion criteria. The overall pooled prevalence of DSD was 30.2%, with a sensitivity analysis of 27.7%. Prevalence varied by country, setting, and tool used for case ascertainment. Our prevalence findings align with previous research but indicate a higher-than-expected rate of DSD in community settings compared to what may be seen in practice. Future research should address the heterogeneity and determine the validity of screening tools.