Systemic Immune-Inflammation Index Predicts 3-Month Functional Outcome in Acute Ischemic Stroke Patients Treated with Intravenous Thrombolysis

Abstract

Background and Purpose

Systemic immune-inflammation index (SII), a novel inflammation index derived from counts of circulating platelets, neutrophils and lymphocytes, has been studied in developing incident cancer. However, the clinical value of SII in acute ischemic stroke (AIS) patients had not been further investigated. Therefore, we aimed to explore the association between SII and severity of stroke as well as 3-month outcome of AIS patients.

Methods

A total of 216 AIS patients receiving intravenous thrombolysis (IVT) and 875 healthy controls (HCs) were retrospectively recruited. Blood samples were collected within 24h after admission. Severity of stroke was assessed by the National Institute of Health stroke scale (NIHSS) scores on admission and poor 3-month functional outcome was defined as Modified Rankin Scale (mRS) > 2.

Results

SII levels in AIS patients were higher than in HCs. The cut-off value of SII is 545.14×10⁹/L. Patients with SII > 545.14×10⁹/L had higher NIHSS scores (median: 5 vs 9, p < 0.001), a positive correlation between SII and NIHSS was observed (rs = 0.305, p < 0.001). Multivariate logistic regression analyses showed that high SII was one of the independent risk factors for poor prognosis at 3 months of AIS patients (OR = 3.953, 95% CI = 1.702–9.179, p = 0.001). The addition of SII to the conventional prognostic model improved the reclassification (but not discrimination) of the functional outcome (net reclassification index 39.3%, p = 0.007).

Conclusion

SII is correlated with stroke severity at admission and can be a novel prognostic biomarker for AIS patients treated with IVT.

Keywords:

• systemic immune-inflammation index
• ischemic stroke
• inflammation
• prognosis

Data Sharing Statement

The datasets used or analyzed during the current study are available from the corresponding author on reasonable request.

Ethics Approval

This study was approved by the Ethics Committee of the Third Affiliated Hospital of Wenzhou Medical University (YJ2020034) and was carried out in accordance with the Declaration of Helsinki.

Consent to Participate

Because this study was retrospectively designed, the ethics committee granted a waiver of the requirement for informed consent for analyzing existing data in accordance with the national legislation and the institutional requirements. For the purpose of privacy protection, personal identification information of enrolled participants was anonymized and replaced with a coding system in this study.

Author Contributions

Conception and study design: LC and GC; data acquisition: YW, TZ, HH, JR, JW, CY, WP, JH, FS, XZ, HQ, YG and BG; data analysis and interpretation: YW, TZ, HH and JR; drafting the article: YW, TZ and HH; revising the article: LC, GC, YW, TZ, HH, JR, JW, CY, WP, JH, FS, XZ, HQ, YG and BG. All authors have made substantial contributions to conception and study design, acquisition of data, or analysis and interpretation of data; have taken part in drafting or critically revised it critically for important intellectual content; agreed to submit to the current journal; reviewed and agreed on all versions to be published; agreed to take responsibility and be accountable for the contents of the article.

Disclosure

Yiyun Weng, Tian Zeng and Honghao Huang are co-first authors for this study. We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted.