Systemic immune-inflammation index as a predictor of early stroke progression/recurrence in acute atherosclerotic ischemic stroke

Objectives: Although the systemic immune-inflammatory index (SII) has recently been correlated with stroke severity and functional outcome, the underlying pathogenesis remains largely unknown. The objective of this study was to explore whether SII could predict early neurologic deterioration (END) in different etiologies of acute ischemic stroke. Materials and methods: From January 2019 to December 2021, a total of 697 consecutive patients with acute ischemic stroke, admitted within 72 hours from stroke onset, were prospectively enrolled. The patients were categorized into 4 groups based on quartiles of SII, calculated as platelets multiplied by neutrophils divided by lymphocytes. END and stroke progression/recurrence were assessed during the first 7 days after stroke onset using predetermined definitions. Logistic regression analysis was conducted to evaluate the association between SII and END, while considering the variation in association across stroke etiologies. Results: END occurred in 135 patients: 24 (3.4%) for Group I, 25 (3.6%) for Group II, 33 (4.7%) for Group III, and 53 (7.6%) for Group IV. Among the END subtypes, stroke progression/recurrence stroke was the most prevalent. In the logistic regression model, the adjusted odds ratios (ORs) of END and stroke progression/recurrence for group IV were 2.51 (95% CI, 1.27-4.95) and 1.98 (95% CI, 1.03-3.89), respectively. Among the stroke etiologies, group IV showed a significant increase in END (OR 4.24; 95% CI, 1.42-12.64) and stroke progression/recurrence (OR 4.13; 95% CI, 1.39-12.27) specifically in case of large artery atherosclerosis. Conclusions: SII independently predicts early stroke progression/recurrence in patients with acute atherosclerotic ischemic stroke.