Abstract / Summary
Abstract Sepsis remains a leading cause of mortality in intensive care units (ICUs). The neutrophil-to-lymphocyte ratio (NLR) and coagulation parameters are dynamic biomarkers of immune activation and hemostatic dysregulation, yet their temporal interplay and prognostic trajectories remain poorly characterized. In this retrospective MIMIC-IV (version 2.2) cohort study, 5,267 adult sepsis patients meeting Sepsis-3 criteria were analyzed, with NLR, platelet count, white blood cell (WBC) count, activated partial thromboplastin time, prothrombin time, and lactate measured daily from ICU day 1 (D1) through D7 and trajectory groups classified by change rate. Overall mortality was 26.7% and 28-day mortality 8.5%. Log-transformed NLR on D1 predicted overall mortality (HR = 1.270, P = 0.002) but was attenuated after multivariable adjustment (HR = 1.125, P = 0.139). Platelet trajectory was the strongest discriminator: decreasing trajectories carried 41.4% versus 20.2% overall mortality (P < 0.001), and the combined “decreasing platelet + increasing WBC” phenotype conferred 48.7% mortality. NLR correlated with fibrinogen (ρ = 0.138), platelet count (ρ = 0.099), and WBC (ρ = 0.085) (all P < 0.001). Platelet trajectory, rather than a single NLR measurement, emerges as the most robust coagulation-related prognostic marker, supporting coagulation-immune crosstalk as a dual-axis prognostic framework warranting prospective validation.