Pan‐Immune‐Inflammation Value for Mortality Risk Stratification in Critically Ill Patients With Acute Ischemic Stroke: A Cohort Study Based on the MIMIC ‐ IV Database

AIMS: The pan-immune-inflammation value (PIV) is an emerging inflammatory biomarker whose prognostic role in critical acute ischemic stroke (AIS) remains unclear. This study aimed to explore the association between PIV and all-cause mortality (ACM). METHODS: This retrospective cohort study enrolled 710 ICU patients with AIS from the MIMIC-IV database. The association between PIV and 90-day (primary), 30-day, and 1-year ACM was evaluated using multivariable Cox regression, restricted cubic splines, subgroup analyses, and sensitivity analyses. RESULTS: Each 1000-unit increase in PIV was independently associated with an 8% higher risk of 90-day ACM (hazard ratio [HR] = 1.08; 95% confidence interval [CI] 1.03-1.13; p < 0.001). A reverse L-shaped nonlinear correlation was observed (threshold: 2987.61). The mortality rate was markedly higher in patients above versus below this threshold (52.7% vs. 28.3%). Subgroup analyses further revealed that this association was significantly stronger in patients without sepsis (p for interaction = 0.007). Both sensitivity analyses-complete-case and multiple imputation-yielded consistent results, confirming the robustness of the main findings. The results remained consistent for 30-day and 1-year ACM. CONCLUSIONS: PIV exhibited a reverse L-shaped relationship with short- and long-term ACM in critical AIS, and served as a tool for ACM risk stratification.