Following PRISMA guidelines, we conducted a systematic review and meta-analysis searching PubMed, Scopus, and Web of Science for prevalence or incidence of delirium in primary and secondary brain tumors. Studies from January 2009 to June 2024 were included. Only high-quality studies were included. We used random-effects models for summary estimates. We performed subgroup analyses by type of tumor, location of tumor, and delirium sub-type. We also analyzed the association of delirium with length of stay. This review was pre-registered on PROSPERO (CRS42024565359).
Of 452 studies screened, 22 were included, representing 35,484 patients. The overall prevalence of delirium in patients with brain tumors was 16% (95% CI 10-24%). The prevalence of delirium in patients with low-grade gliomas, high-grade gliomas, and brain metastases were 10%, 24%, and 43% respectively. Compared to the occipital lobe, the highest relative risk for delirium occurred for tumors in the limbic system (RR 5.01; 95% CI 1.88-16.35), then frontal (RR 3.01, CI 1.33, 7.89), and temporal (RR 2.94, CI 1.27-7.83) lobes. were more likely to have hypoactive (RR 5.20, 95% CI 3.74-7.44) or hyperactive delirium (RR 3.24, 95% CI 2.29-4.67) rather than mixed. Delirium was associated with an increased length of stay (4.62 days longer; 95% CI 3.23-6.01). There was large heterogeneity across studies.