Prevalence of delirium among patients with advanced cancer: a systematic review and meta-analysis

Delirium is a prevalent complication experienced by patients with advanced cancer and is associated with various adverse outcomes. Although delirium is widely reported among patients with advanced cancer, its estimated prevalence shows considerable heterogeneity across studies. This study aimed to determine the prevalence of delirium among patients with advanced cancer.

A comprehensive literature search was conducted across ten major electronic databases from their inception to September 15, 2025. Data extraction was undertaken using a structured data collection form, and methodological quality was assessed using the Joanna Briggs Institute (JBI) critical appraisal tool for prevalence studies. A random-effects model was used to estimate the pooled prevalence of delirium. Heterogeneity was evaluated using the I ² statistic, with subgroup analyses performed to explore its potential sources.

A total of 17 studies comprising 9,007 patients with advanced cancer yielded a pooled delirium prevalence of 35.6% (95% CI: 27.2-44.1). 13 studies were appraised as having a low overall risk of bias, while 4 were considered to have a moderate risk of bias. The results of subgroup analysis indicated that the pooled prevalence of delirium among patients with advanced cancer exhibited significant variation depending on the assessment tool employed.

Our findings indicated that delirium is highly prevalent among patients with advanced cancer, highlighting the necessity for early screening, prevention, and treatment. However, these results should be interpreted with caution due to limitations such as the small sample size and considerable heterogeneity. Moreover, the inclusion of only three studies from developing countries limits generalizability to low-resource settings.

https://www.crd.york.ac.uk/PROSPERO/view/CRD420251167526.