Admission and Day-7 Inflammatory and Hematological Indices in Critically Ill Patients with Acute Ischemic Stroke: A Retrospective Cohort Study

Background and Objectives: Routinely available inflammatory and hematological indices may carry prognostic information in critically ill patients with acute ischemic stroke (AIS). We explored associations of indices measured at ICU admission and on day 7 with intensive care unit (ICU), 30-day, and 180-day mortality. Materials and Methods: This retrospective single-center cohort study included adult AIS patients admitted to a tertiary ICU between August 2017 and August 2022. Derived indices included neutrophil percentage-to-albumin ratio (NPAR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), LDH-to-albumin ratio (LAR), CRP-to-albumin ratio (CAR), neutrophil-to-lymphocyte ratio (NLR), and systemic immune-inflammation index (SII). The primary outcome was ICU mortality; 30-day and 180-day mortality were secondary outcomes. Day-7 analyses used outcome-specific landmark populations (n = 51 for ICU mortality; n = 68 for 30-day and 180-day mortality). Adjusted logistic models were evaluated with Benjamini–Hochberg false discovery rate (FDR) correction, and Cox regression was used for 180-day mortality. Results: Among 71 patients, ICU, 30-day, and 180-day mortality was 42.3%, 19.7%, and 45.1%. Admission NPAR showed nominal associations with ICU and 180-day mortality after clinical adjustment, but neither remained significant after FDR correction. At day 7, CAR7 and NPAR7 remained associated with subsequent ICU mortality after FDR correction (q = 0.035 and q = 0.028, respectively); other nominal logistic associations did not. In Cox regression analysis, admission NPAR remained associated with 180-day mortality after FDR correction (HR = 1.062, 95% CI 1.025–1.100). Conclusions: After FDR correction, CAR7 and NPAR7 remained associated with subsequent ICU mortality. Admission NPAR was also associated with 180-day mortality in Cox analysis. These findings are exploratory and hypothesis-generating and warrant confirmation in larger, prospective, externally validated cohorts.