Neutrophil-to–high-density lipoprotein cholesterol ratio as a predictor of outcomes after successful endovascular reperfusion in acute ischemic stroke

Background and objective: A substantial proportion of patients experience poor functional outcomes despite successful reperfusion after endovascular therapy (EVT) for acute ischemic stroke (AIS). Systemic inflammation and lipid metabolism are thought to contribute to reperfusion-related injury. We aimed to evaluate the association between the neutrophil-to-high-density lipoprotein cholesterol ratio (NHR) and clinical outcomes in AIS patients who achieved successful reperfusion, and to assess its incremental prognostic value beyond established clinical predictors. Methods: In this single-center retrospective cohort study, 367 AIS patients with successful reperfusion (mTICI 2b-3) after EVT were included. NHR was calculated from baseline blood samples. The primary outcome was poor functional outcome at 90 days (modified Rankin Scale score 3-6). Secondary outcomes included 90-day mortality and symptomatic intracranial hemorrhage (sICH). Associations between NHR and outcomes were examined using logistic regression models with NHR analyzed primarily as a continuous variable, and restricted cubic splines were used to explore potential nonlinearity. Model performance was evaluated by comparing a baseline clinical model with and without NHR using area under the receiver operating characteristic curve (AUC), DeLong tests, calibration metrics, and bootstrap internal validation. Results: Higher NHR was associated with an increased risk of poor functional outcome after multivariable adjustment (adjusted OR per 1-unit increase, approximately 1.34), indicating a modest effect size. The association with mortality was weaker and showed limited incremental discriminative value beyond baseline clinical predictors. For sICH, the association was attenuated after adjustment and should be interpreted cautiously. Spline analyses suggested possible nonlinearity at higher NHR levels, although confidence intervals widened in these ranges, indicating uncertainty due to sparse data. Adding NHR to the baseline clinical model improved discrimination for poor functional outcome, but the absolute AUC values indicated only moderate predictive performance, and discrimination for mortality and sICH remained weak to modest. Conclusion: In AIS patients who achieved successful reperfusion after EVT, higher NHR was associated with poorer 90-day functional outcomes, with modest effect sizes and limited incremental prognostic value beyond established clinical markers. NHR should be interpreted as a complementary risk marker rather than a standalone predictive or clinical decision-making tool, and external validation is required before any clinical application.