ObjectiveTo evaluate the prognosis values of systemic immune–inflammation index (SII) in non-chronic cerebral venous sinus thrombosis (CVST).Methodspatients with CVST, admitted to the First Affiliated Hospital of Zhengzhou University, were retrospectively identified from January 2013 to December 2018. We selected patients in acute/subacute phase from database. Functional outcomes of patients were evaluated with the modified Rankin Scale (mRS)—mRS 3–6 as poor outcomes and mRS 6 as death. The overall survival time was defined as the date of onset to the date of death or last follow-up date. Survival analysis was described by the Kaplan-Meier curve and Cox regression analysis. Multivariate logistic regression analysis assessed the relationship between SII and poor functional outcome. The area under the Receiver Operating Curve curve (AUC) was estimated to evaluate the ability of SII in prediction.ResultsA total of 270 patients were included and their duration of follow-up was 22 months (6–66 months), of whom 31 patients had poor outcomes and 24 patients dead. Cox regression analysis showed that SII (HR=1.304, 95% CI: 1.101 to 1.703, p=0.001) was a predictor of death in non-chronic CVST. Patients with higher SII presented lower survival rates (p=0.003). The AUC of SII was 0.792 (95% CI: 0.695 to 0.888, p=0.040) with a sensitivity of 69.6% and specificity of 80.1%. Subgroups analysis demonstrated that SII was an important predictor of poor outcomes in male (OR=1.303, 95% CI: 1.102 to 1.501, p=0.011) and pregnancy/puerperium female (OR=1.407, 95% CI: 1.204 to 1.703, p=0.034).ConclusionsSII was a potential predictor in the poor prognosis of patients with acute/subacute CVST, especially in male and pregnancy/puerperium female.