EXPRESS: Association of Systemic Immune-Inflammatory Index (SII) and Systemic Inflammatory Response Index (SIRI) with Mortality in Ischemic Stroke Patients: A Meta-analysis

This study aimed to evaluate the association of the systemic inflammatory response index (SIRI) and the systemic immune-inflammatory index (SII) with mortality in ischemic stroke (IS) patients.Embase, Cochrane Library, PubMed, and Web of Science were searched up to January 20, 2025. Outcomes were the associations of SII and SIRI with 30-day, 90-day, 1-year, all-cause, and in-hospital mortality in acute IS. Quality was assessed with the Newcastle-Ottawa Scale, and statistical analysis with Stata 18.Heterogeneity was assessed using I² and Q tests (random-effects if I² ≥ 50% or P < 0.10), with sensitivity and publication bias tests performed. Classification of 'high'/'low' SII/SIRI followed each study's definition due to a lack of unified standards. Ten articles, encompassing 46,353 patients, were included in this meta-analysis. When analyzed as categorical data, high levels of SII were a risk factor for 90-day (hazard ratio [HR]=2.56, 95% confidence interval [CI]=1.81-3.62, P<0.001), 1-year (HR=2.31, 95% CI=1.59-3.36, P<0.001), all-cause (HR=1.32, 95% CI=1.20-1.46, P<0.001), and in-hospital mortality (HR=1.74, 95% CI=1.30-2.33, P<0.001) in individuals with IS. High levels of SIRI were a risk factor for 30-day (HR=1.41, 95% CI=1.23-1.61, P<0.001), 90-day (HR=1.49, 95% CI=1.32-1.69, P<0.001), and 1-year mortality (HR=1.38, 95% CI=1.24-1.53, P<0.001) in individuals with IS. However, when analyzed as continuous data, neither SII nor SIRI was significantly associated with all-cause mortality in IS patients (P>0.05).This meta-analysis demonstrated that high levels of SII and SIRI are associated with mortality in IS patients, aiding mortality risk assessment and clinical decision-making. Larger, prospective, multicenter studies are warranted for further validation.