BACKGROUND: Aneurysmal subarachnoid hemorrhage (aSAH) is a common neurosurgical disorder with high morbidity and poor prognosis, and the associated delayed cerebral ischemia (DCI) is a key factor contributing to poor prognosis. Despite extensive research on the risk factors associated with DCI development, the evidence remains conflicting. Therefore, this meta-analysis of case-control studies aimed to investigate the risk factors for DCI occurrence during hospitalization in patients with aSAH. METHODS: We systematically searched PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials for eligible studies published before November 20, 2023. Two independent reviewers extracted relevant data from the included studies using a pre-established data extraction form. The primary outcome was DCI occurrence during hospitalization in patients with aSAH. RESULTS: A total of 42 studies involving 21,726 patients with aSAH were included. The pooled meta-analysis showed that female sex
Hunt-Hess, modified Fisher, and World Federation of Neurosurgical Societies scale scores of 4-5, 3-4, and 4-5, respectively
vasospasm
combined intraventricular hemorrhage
pre-existing hypertension
hydrocephalus
intracranial infections
and high white blood cell count on admission were independent risk factors for the development of postoperative DCIs in patients with aSAH. CONCLUSIONS: Patients with aSAH who have a Hunt-Hess scale score ≥4, a modified Fisher scale score ≥3, a WFNS scale score ≥4, intraventricular hemorrhage, pre-existing hypertension, cerebral vasospasm, a high white blood cell count on admission, intracranial infection, and female sex are at high risk of DCI and hence should be carefully monitored in the intensive care unit.