Neutrophil Percentage-to-Albumin Ratio as a Prognostic Marker for Mortality in Ischemic Stroke Patients

Background: The neutrophil percentage-to-albumin ratio (NPAR) is an emerging inflammatory biomarker that has demonstrated a significant association with poor outcomes in patients with cardiovascular diseases. However, the existing evidence regarding its prognostic value in ischemic stroke (IS) patients remains limited. Our study aimed to investigate the potential of the NPAR as a prognostic indicator for all-cause mortality in patients with IS. Methods: This study screened IS patients from the Medical Information Mart for Intensive Care (MIMIC-IV) database and categorized them into two groups based on NPAR values, employing propensity score matching to mitigate confounding factors. The primary outcome assessed was 90‒day mortality, and the secondary outcomes included in-hospital mortality, ICU mortality, and mortality at 30‒day and 1‒year after admission. Cox proportional hazards regression analysis and restricted cubic splines were used to explore the relationship between the NPAR and all-cause mortality in critically ill IS patients, whereas Kaplan‒Meier analysis was used to estimate survival curves. Subgroup analysis and interaction tests were performed to evaluate the robustness of the results. Receiver operating characteristic curves were computed to assess the diagnostic value of the NPAR in predicting outcomes. Results: A total of 706 patients (53.3% male) were included in the study, with in-hospital and ICU mortality rates of 18.2% and 12.6%, respectively. The mortality rates at 30‒day, 90‒day, and 1‒year were 19.2%, 29.7%, and 37.8%, respectively. Restricted cubic splines indicated a nonlinear increase in all-cause mortality as the NPAR increased. Multivariate Cox regression analysis revealed a significant association between a high NPAR and all-cause mortality at 90‒day (hazard ratio [HR]: 1.99; 95% confidence interval [95% CI]: 1.44-2.76, p < 0.001), 30‒day (HR: 2.09; 95% CI: 1.39-3.13, p < 0.001), and 1‒year (HR: 1.77; 95% CI: 1.32-2.37, p < 0.001). The subgroup analysis indicates that a significant interaction was observed between hypertension and mortality risk in IS patients (p for interaction = 0.012), suggesting that hypertension may be an important predictor of poor prognosis in these patients. Receiver operating characteristic curves demonstrated that the NPAR provides a modestly greater ability to predict the risk of death in patients with IS compared to the individual indices of neutrophil percentage and albumin levels, although the specificity (0.567) and sensitivity (0.684) of NPAR were not outstanding overall. Conclusion: Our study revealed an independent association between a high NPAR and increased all-cause mortality at 30‒day, 90‒day, and 1‒year and during hospitalization in patients with IS, reinforcing its status as an independent determinant of mortality risk.