Neutrophil-to-Lymphocyte Ratio, Platelet-to-Lymphocyte Ratio, Systemic Immune Inflammation Index and Efficacy of Remote Ischemic Conditioning in Acute Ischemic Stroke: A Post Hoc Exploratory Analysis of the RICAMIS Study.

Background: We conducted a post-hoc analysis of the RICAMIS trial to investigate the effect of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune inflammation index (SII) on the efficacy of remote ischemic conditioning treatment. Methods: In this post-hoc analysis, NLR, PLR, and SII were measured before randomization. Patients were divided into two groups based on their cut-off values: high vs low NLR, high vs low PLR, and high vs low SII groups. Each group was further subdivided into RIC and control groups. The primary endpoint was a poor outcome (mRS 2-6 at 90 days). Differences in the primary endpoint between the RIC and control subgroups were compared, and the interactions of treatment assignment with NLR, PLR, and SII were evaluated. Results: A total of 1679 patients were included in the final analysis. Compared with the control group, RIC significantly improved functional outcomes regardless of the inflammation status. The improved probability of poor outcome in the RIC vs control group was numerically greater in the high vs low inflammation group (NLR, 7.8% vs 5.1%; PLR, 7% vs 6.5%; SII, 9% vs 5.3%). However, we did not find an interaction effect of an intervention (RIC or control) with different NLR, PLR, or SII on clinical outcomes (P > 0.05). In addition, the NLR and SII were independently associated with functional outcomes in all patients, regardless of whether they received RIC. Conclusion: Inflammation may not affect the efficacy of RIC in patients with acute moderate ischemic stroke, although a lower probability of poor outcome at 90 days was identified in patients with a high vs low inflammatory status.