Abstract: Objective To explore the correlation between neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), systemic inflammatory response index (SIRI), and the 6-month prognostic trajectories in elderly patients with ischemic stroke. Methods This study enrolled 200 patients with ischemic stroke from two tertiary hospitals in Suzhou, China. Prognosis was assessed using the Modified Rankin Scale (mRS) at 14 days, 1 month, 3 months, and 6 months after admission. Based on multi-timepoint mRS scores, a Latent Class Growth Model (LCGM) was employed to identify distinct prognostic trajectory classes. NLR, PLR, and SIRI were categorized into quartiles, and their associations with prognostic trajectories were analyzed using ordered logistic regression. Restricted cubic spline analysis was applied to examine the dose-response relationship between inflammatory markers and prognostic trajectories. Patients were further divided into high- and low-value groups based on median levels of each marker. A composite inflammatory index (0, 1, 2, or 3 high inflammatory markers) was constructed to evaluate its association with prognostic trajectories. Results LCGM identified a best model including three distinct stroke outcome trajectory categories. After multivariable adjustment, elevated levels of NLR, PLR, and SIRI were all significantly associated with an increased risk of unfavorable outcome progression trends (P<0.05). Compared to the group with 0 elevated inflammatory markers, the group with 3 elevated inflammatory markers showed a significantly higher risk of unfavorable outcome progression. Conclusions Elevated NLR, PLR, and SIRI levels, as well as an increased number of elevated inflammatory markers, were significantly associated with a higher risk of unfavorable outcome progression in elderly patients with ischemic stroke.

Key words: ischemic stroke, neutrophil to lymphocyte ratio, platelet to lymphocyte ratio, systemic inflammatory response index, prognostic trajectory, predictive value