[The predictive value of the systemic immune inflammatory response index and interleukin-6 for postoperative hydrocephalus in patients with aneurysmal subarachnoid hemorrhage].

Objective

To investigate the predictive value of systemic immune inflammatory response index (SII) and interleukin-6 (IL-6) for postoperative hydrocephalus in patients with aneurysmal subarachnoid hemorrhage (aSAH).

Methods

This is a retrospective cohort study. The clinical data of 209 aSAH patients who underwent surgical treatment at the People's Hospital of Xinjiang Uygur Autonomous Region from June 2023 to June 2025 were enrolled, including 83 males and 126 females, with an age of (58.5±6.0) years (range: 29 to 78 years). Patients were divided into a hydrocephalus group and a non-hydrocephalus group based on the occurrence of hydrocephalus 3 months postoperatively. Preoperative baseline data, treatment modality, and SII and IL-6 levels on postoperative day 3 were collected. Intergroup comparisons were performed using the independent sample t-test or χ2 test. Multivariate Logistic regression analysis was used to identify independent influencing factors for postoperative hydrocephalus in aSAH patients, and receiver operating characteristic (ROC) curves were used to evaluate the predictive efficacy of SII, IL-6, and their combination for hydrocephalus.

Results

Among the 209 aSAH patients, 56 developed hydrocephalus 3 months postoperatively, with an incidence rate of 26.8%. There were no statistically significant differences between the two groups in sex distribution, smoking history, alcohol consumption history, diabetes history, treatment modality, or aneurysm location (all P>0.05). The proportions of hypertension history, Hunt-Hess grade Ⅲ to Ⅳ, and modified Fisher grade Ⅲ to Ⅳ in the hydrocephalus group were higher than those in the non-hydrocephalus group (all P<0.05). The Glasgow coma scale (GCS) score in the hydrocephalus group was lower than that in the non-hydrocephalus group ((8.12±1.09)points vs. (9.04±1.56) points, t=4.062,P<0.01), and the SII and IL-6 levels were higher than those in the non-hydrocephalus group (all P<0.05). Multicollinearity analysis showed that hypertension history (tolerance=0.075, VIF=12.136) and GCS score (tolerance=0.098, VIF=11.314) exhibited multicollinearity, and variables with multicollinearity were excluded. Age, Hunt-Hess grade, modified Fisher grade, SII, and IL-6 were included as independent variables in the multivariate Logistic regression model, with postoperative hydrocephalus in aSAH patients as the dependent variable (yes=1, no=0). The results indicated that Hunt-Hess grade, SII, and IL-6 were independent risk factors for postoperative hydrocephalus in aSAH patients (all P<0.05). ROC curve analysis showed that the area under the carve (AUC) for SII, IL-6 alone, and their combination in predicting postoperative hydrocephalus in aSAH patients were 0.789, 0.743, and 0.859, respectively. The AUC of the combined prediction was greater than that of SII or IL-6 alone (Z=2.571, P=0.010; Z=3.149, P=0.002).

Conclusion

Elevated SII and IL-6 levels are independent risk factors for postoperative hydrocephalus in aSAH patients, and the combined detection of the two can enhance predictive efficacy.