Abnormal Platelet-to-Lymphocyte Ratio is Associated with Poor Outcomes in Pediatric Sepsis.

Sepsis remains a major cause of morbidity and mortality in children, necessitating an early risk assessment to prevent delayed treatment and achieve optimal outcomes. This study investigated the association between systemic immune-inflammatory indices and clinical outcomes in children with sepsis. Single-center, retrospective cohort study. Pediatric intensive Care Unit (PICU) of a tertiary care children's hospital from 2015 to 2023. Children aged 0-18 years admitted with sepsis. Patients were excluded if they lacked a complete blood count with differential on admission. 420 patients were included. The platelet-to-lymphocyte ratio (PLR) was associated with higher mortality HR:1.001 (1.000-1.002), p:0.032. Incorporating PLR into the Pediatric Index of Mortality (PIM) score improved the model discrimination for mortality (AUROC 0.705 vs. 0.774; AUPRC 0.202 vs 0.257). Similarly, adding PLR to the PRISM-III improved AUROC from 0.648 to 0.697. High PLR was also associated with higher odds of requiring intubation (OR 2.42, p:0.005) and extracorporeal membrane oxygenation (OR 4.74, p:0.002) and with decreased sub distribution hazard of extubation, ICU discharge, and hospital discharge alive at 28 days (SHR: 0.89, 0.72, and 0.76 respectively; all p < 0.005). High PLR at admission was independently associated with worse clinical outcomes in pediatric patients with sepsis. Adding PLR to PIM and PRISM III enhanced the predictive performance. PLR is a simple and readily available index that may improve early risk stratification in this high-risk population.