Systemic Inflammatory Response Index and the Short-Term Functional Outcome of Patients with Acute Ischemic Stroke: A Meta-analysis

Introduction: The systemic inflammatory response index (SIRI) is a novel indicator of systemic inflammation derived from the absolute counts of neutrophils, monocytes, and lymphocytes. The aim of this meta-analysis was to evaluate the association between SIRI and functional outcome in patients with acute ischemic stroke (AIS). Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed in this meta-analysis. Relevant cohort studies were retrieved by a search of electronic databases including PubMed, Web of Science, Embase, Wanfang, and China National Knowledge Infrastructure from database inception to February 9, 2024. A poor functional outcome was defined as a modified Rankin Scale >= 3 within 3 months after disease onset. A random-effects model was used to combine the data by incorporating the influence of between-study heterogeneity. The protocol of the meta-analysis was not prospectively registered in PROSPERO. Results: Fourteen cohort studies were included. Pooled results showed that a high SIRI at admission was associated with increased risk of poor functional outcome within 3 months (odds ratio [OR]: 1.57, 95% confidence interval: 1.39 to 1.78, p < 0.001; I2 = 0%). Results of the meta-regression analysis suggested that the cutoff for defining a high SIRI was positively related to the OR for the association between SIRI and the risk of poor functional outcome (coefficient = 0.13, p = 0.03), while other variables including sample size, mean age, severity of stroke at admission, percentage of men, current smokers, or patients with diabetes did not significantly modify the results. Subgroup analyses according to study design, main treatments, and study quality scores showed similar results. Conclusion: A high SIRI may be associated with a poor functional outcome in patients after AIS.