Seizure incidence of angiogram-negative subarachnoid hemorrhage: An updated meta-analysis.

To provide updated information on seizure events and patterns in patients with angiogram-negative subarachnoid hemorrhage (SAH) based on the initial hemorrhage patterns: perimesencephalic SAH (PMH) versus non-PMH.A review of online database literature from January 1990 to November 2017 was systematically performed. In case of heterogeneity <50%, a fixed effect model was used. Publication bias was determined using Begg's funnel plot and the Trim and Fill method.A total of 9 studies with 645 patients were included for final analysis after excluding one study without any seizure within either cohort. PMH patients had lower seizure rates (odds-ratio [OR] = 0.393; 95% confidence interval [CI]: 0.158-0.978) compared to non-PMH patients. The funnel plot showed a relatively asymmetric pattern, suggesting possible publication bias. After correction of the forest plot, the adjusted OR was 0.362 (95% CI: 0.148-0.886), indicating significant relationships between PMH and lower incidence of seizure.PMH is associated lower seizure risk than non-PMH. However, possible publication bias could be a concern to the interpretation. Additional meta-analyses based on individual patient data from prospective large-scale studies are necessary.