Inflammatory Burden Index: Association Between Novel Systemic Inflammatory Biomarkers and Prognosis as Well as in-Hospital Complications of Patients with Aneurysmal Subarachnoid Hemorrhage

Zhenshan Song,1,&ast; Fa Lin,1,&ast; Yu Chen,1 Tu Li,1 Runting Li,1 Junlin Lu,1 Heze Han,1 Ruinan Li,1 Jun Yang,1 Zhipeng Li,1 Haibin Zhang,1 Kexin Yuan,1 Ke Wang,1 Yunfan Zhou,1 Yitong Jia,1 Xiaolin Chen1– 3 1Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People’s Republic of China; 2Stroke Center, Beijing Institute for Brain Disorders, Beijing, People’s Republic of China; 3Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Xiaolin Chen, Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, No. 119 South Fourth Ring West Road, Fengtai District, Beijing, 100070, People’s Republic of China, Email chenxiaolin@bjtth.orgPurpose: Systemic inflammation plays an important role in the pathophysiology and progression of aneurysmal subarachnoid hemorrhage (aSAH). In this study, we aimed to investigate the association between a new biomarker, the inflammatory burden index (IBI) and the prognosis as well as in-hospital complications of aSAH patients.Patients and Methods: We analyzed data from patients with aSAH between January 2019 and September 2022 who were included in the LongTEAM (Long-term Prognosis of Emergency Aneurysmal Subarachnoid Hemorrhage) registry study. The IBI was formulated as C-reactive protein × neutrophils/lymphocytes. The unfavorable functional prognosis was assessed by the modified Rankin Scale (mRS). Receiver operating characteristic (ROC) curve analysis was conducted to determine the optimal cut-off values for IBI to distinguish the unfavorable functional prognosis. Multivariate logistic regression was applied to investigate the association between IBI and in-hospital complications. Propensity score matching was adjusted for imbalances in baseline characteristics to assess the effect of IBI on prognosis.Results: A total of 408 consecutive patients with aSAH enrolled in the study, of which 235 (57.6%) were female patients and the mean age was 55.28 years old. An IBI equal to 138.03 was identified as the best cut-off threshold to distinguish the unfavorable prognosis at 3 months (area under the curve [AUC] [95% CI] 0.637 [0.568– 0.706]). ln IBI was independently associated with 3-month functional prognosis (OR [95% CI] 1.362 [1.148– 1.615]; P< 0.001), pneumonia (OR [95% CI] 1.427 [1.227– 1.659]; P< 0.001) and deep venous thrombosis (DVT). (OR [95% CI] 1.326 [1.124– 1.564]; P=0.001). After propensity score matching (57:57), an increased proportion of patients with IBI ≥ 138.03 had a poor functional prognosis at 3 months and in-hospital complications including developed pneumonia and DVT.Conclusion: In patients with aSAH, high IBI level at admission was associated with unfavorable functional prognosis as well as pneumonia and deep vein thrombosis.Keywords: aneurysmal subarachnoid hemorrhage, inflammatory burden index, functional prognosis, complications